HI-YIELD FACTS IN ANATOMY [from MOORE & USMLE-ANATOMY roadmap] CHAPTER 1 – BASIC STRUCTURES AND CONCEPTS
SKELETAL SYSTEM
Composed of 206 individual bones [80 - axial, 126 – appendicular]
Functions: support, attachment, protection, storage [calcium, phosphorus], hemopoiesis
Axial skeleton Appendicular skeleton
Skull, vertebral column, rib cage, hyoid, auditory ossicles
Pectoral girdle and pelvic girdle, bones of the upper and lower extremities BONES – consists of cancellous [spongy] and compact bone
Classification Examples
Long bones Clavicle, bones of extremities [except carpals, tarsals] Short bones Carpal bones [hand], tarsal bones [foot]
Flat bones Ribs, sternum, scapula, calvaria Irregular bones Vertebrae, hip bones, skull bones Sesamoid bones Patella
Clinical notes Fracture
Due to trauma or atrophy from either osteoporosis [loss of bone mass] or disuse. Leads to avascular necrosis [loss of bone tissue caused by disruption of arterial supply] JOINTS – where 2 or more skeletal elements meet [either bone or cartilage]
Innervated according to HILTON’s law [nerves that supply muscles that move a joint also supply the joint and skin]
Classification Types Examples Fibrous Sutures
Syndesmoses Skull
Tibiofibular, tympanostapedial joints Cartilaginous synchondroses
symphysis Epiphyseal plates, sphenooccipital synchondrosesPubic symphysis, vertebral joints Synovial Plane/gliding Hinge/ginglymus Pivot / trochoid Condyloid Ellipsoid Saddle Ball + socket
Intercarpal, sternoclavicular, acromioclavicular Elbow, knee, ankle joints
Atlantoaxial, superior and inferior radioulnar Metacarpo/metatarsophalangeal,atlantooccipital Radiocarpal/wrist joint
Carpometacarpal joint of thumb
Shoulder and hip joints [aka enarthroidal joint] Clinical notes
Bursitis – inflammation of bursa results in bursitis w/c may limit movement of a joint. MUSCULAR SYSTEMSmooth Cardiac Skeletal
Involuntary, nonstriated Involuntary, striated Voluntary, striated In viscera, blood vessels In myocardium of heart Anywhere in the body Modulated by autonomic
nerves, hormones, or mechanical stimulation
Does not receive direct innervations [contraction is innervated by autonomic n. Other structures:
Tendon Connects muscle to bone or cartilage
Ligament CT band that crosses a joint binding the articulating bones Clinical notes
Myasthenia gravis
Antibodies attack acetylcholine receptors resulting in defective neuromuscular transmission. S/Sx: bilateral ptosis, horizontal diplopia, dysphagia, dysarthria, and weakness in chewing and
in musles of facial expression. Proximal limb muscles may be affected. Cardiac and smooth muscle are spared.
Most of them have thymic hyperplasia or thymoma.
Tx: Acetylcholinesterase inhibitors allowing acetylcholine to remain in synaptic cleft longer. Lambert-Eaton syndrome
An immunologic disorder of Ca+ channels in nerves at the end plate
Proximal muscles in limbs are primarliy affected; muscles innervated by CN are spared. Repetitive contractions of affected muscles temporarily increase in strength. Associated w/ small cell CA of the lung
VASCULAR SYSTEM A. Blood vascular system
Functions: carries oxygen, absorbed nutrients and waste products, promotes healing
Pulmonary circulation Systemic circulation
Transports blood from R side of heart to lungs
and back to L side of heart Transports blood from L side of heart to the body [except lungs] and back to R side of heart Facilitates exchange of O2 & CO2 in LUNGS Facilitates exchange of O2 & CO2 in TISSUES R ventricle, pulmonary arteries, capillaries, L ventricle, R atrium, all arteries, capillaries,
veins and L atrium veins [except of pulmonary circulation] ARTERIES – carry blood from heart to all areas of the body
Type Functions Examples
Elastic Conducting arteries Aorta, pulmonary trunk, common carotid & subclavian A Muscular Distributing arteries All other arteries
Arterioles w/ precapillary sphincter Anywhere in the body
CAPILLARIES – smallest of the blood vessels, site of exchange between tissues and blood VEINS – carry blood back to heart from peripheral tissues
Type Characteristics
Venules w/ valves, smallest type, from confluence of several capillaries Small veins w/ valves and smooth muscle in their walls
Medium veins w/ valves and connective tissue + smooth muscle Large veins No valves, w/ abundant elastic fibers and smooth muscle Other components:
SINUSOIDS – discontinuous capillaries larger than ordinary capillaries, found in adrenal & pituitary glands, liver, spleen, and bone marrow
PORTAL SYSTEM – system of vessels interposed between 2 capillary beds, includes hepatic-portal system and hypophyseal-hepatic-portal system
LYMPHOID SYSTEM
Functions: returns tissue fluids to venous system, provides immunologic defense & route for lymphocytes + absorbed fats, important route for spread of malignant tumor.
All lymph enters the venous system at the junction of internal jugular V. and subclavian V. in the neck via R lymphatic duct on R side and thoracic duct on the L.
Tissues that lack blood vessels also lack lymphatic vessels w/c include: epidermis, cartilage, CNS and thymus.
Type Example Functions Lymph
vessels Rightlymphatic duct
Receives lymph from R side of head and neck through R jugular lymph trunk, R upper extremity thru R subclavian trunk, R thoracic cavity thru R bronchomediatinal trunk
Lymph
nodes Thoracic duct Receives lymph from most of the body below diaphragm, L and lower R posterior intercostals spaces, L side of neck thru L internal jugular trunk, L upper extremity thru L subclavian trunk, and L side of thoracic cavity thru L bronchomediastinal trunk
NERVOUS SYSTEM Classificatio
n Features
Central NS Brain + spinal cord composed of gray matter [myelinated axons and neuroglia], and white matter [neuronal bodies and dendrites + neuroglia]
Peripheral NS Afferent [conduct impulses from sensory receptors towards CNS], and efferent / motor neurons [impulses away from CNS to periph. end organ]
Somatic NS Control voluntary activities Visceral NS Control visceral activities Other components:
Astrocytes – physical support, repair, K+ metabolism, help maintain BBB. Its marker is GFAP. Microglia – for phagocytosis
Neuron/nerve cell – functional unit of nervous system, for communication. Ganglion – collection of neuronal cell bodies outside CNS.
Oligodendrocytes – glial cells that form central myelin for parts of multiple axons in the CNS. Schwann cells – are glial cells that form peripheral myelin for axons or processes in the PNS. Ependymal cells – lines inner lining of ventricles
CNS axons do not regenerate if cut while myelinated axons in PNS does regenerate down. Clinical notes
Multiple sclerosis
Both sensory and motor systems containing axons w/ myelin formed by oligodendrocytes undergo an inflammatory reaction that impairs or blocks impulse transmission.
Sensory and motor deficits can be seen in all areas of the body.
CN 2/optic nerve is affected because all of the myelin sheaths of its axons are formed by oligodendrocytes. Optic neuritis is the presenting sign.
Corticosteroid administration promotes remission. Guillain-Barre syndrome
Myelin formed by Schwann cells in PNS undergoes acute inflammatory reaction after a respiratory or gastrointestinal illness. This also impairs or blocks impulse transmission.
Motor axons are always affected producing weakness in limbs. Weakness of CN 6 and 7 or respiratory muscles may be seen. Sensory deficits are mild or absent.
Antibodies to peripheral myelin are removed by plasmapheresis or autoimmune attack is blocked by administration of gamma globulin. Patients often completely recover.
Schwannomas
Benign encapsulated schwannomas of vestibular nerve [CN 8] may develop affecting hearing and balance. Large acoustic schwannomas may compress facial nerve [CN 7] or trigeminal nerve [CN V].
CRANIAL NERVES - 12 pair’s w/c arise from brainstem: sensory = CN 1, 2, 8; motor = CN 3, 4, 6, 11, 12; mixed = CN 5, 7, 9, 10. [Refer to Netter p. 112]
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Name Lesions result in Functions
CN 1 – olfactory [S] Anosmia Smell
CN 2 – optic [S] Anopsia, loss of light reflex w/ CN 3
Vision, Only nerve affected by multiple sclerosis
CN 3 – oculomotor [M] Diplopia, external strabismus, loss of parallel gaze, ptosis, loss of near response
EOM: SR, IR, MR, IO, LPS [except LR and SO]
Accommodation of near vision CN 4 – trochlear [M] Diplopia, difficulty reading,
going down stairs, head tilting EOM: superior oblique CN 5 – trigeminal
[mixed] Loss of sensation in skin of forehead, scalp, cornea, maxilla, mandible, tongue, loss of blinking reflex, chewing loss
Sensation to scalp, face, jaw, oral Movements of masticators, facial CN 6 – abducens [M] Diplopia, internal strabismus,
loss of parallel gaze EOM: lateral rectus – adducts eyeball CN 7 – facial [mixed] Mouth drooping, cannot close
the eye, wrinkle forehead, loss of blink reflex, hyperacusis, altered taste, reduction of saliva and other secretions
Facial expression muscles Secretomotor [salivary glands] Taste: anterior 2/3 of tongue Visceral sensation: body Somatic sensation: ear CN 8 – cochlear
Vestibulocochlear [S] Sensorineural hearing loss, loss of balance, nystagmus Equilibrium [linear & angular acceleration], balance, hearing CN 9-
glossopharyngeal [mixed]
Loss of sensory limb of GAG reflex w/ CN 10
Reduction of saliva
Stylopharyngeus muscle Secretomotor: parotid gland Taste: posterior 1/3 of tongue Visceral: pharynx, 1/3 of tongue Somatic: tympanic membrane CN 10 – vagus
[mixed] Nasal speech, nasal regurgitation, palate droop, deviation of uvula away from lesioned nerve, dysphagia, loss of GAG reflex w/ CN 9, loss of cough reflex, miosis, anhydrosis, & ptosis [Horner’s]
Pharynx, larynx, soft palate Cardiac, smooth, glands Taste over epiglottis Visceral sensation and reflexes Somatic: ear and dura CN 11 – accessory
Spinal portion Weakness in turning head to opposite side, shoulder droop, difficulty in combing the hair
Joins vagus to larynx distribution Sternocleidomastoid, trapezius CN 12 - hypoglossal Tongue deviation on protrusion
toward leisioned nerve Intrinsic’/extrinsic tongue m. [except palatoglossus] Clinical notes
Olfactory N. lesions
May cause hyposmia, dysosmia or anosmia.
Olfactory deficits may be caused by a fracture of cribriform plate; w/c damages the primary olfactory neurons.
Fracture of cribriform plate may also tear the meninges [of the olfactory bulb and result in CSF rhinorrheadischarge of CSF from the nostrils].
Oculomotor N. lesions
Caused by compression by a herniated part of hemisphere or by a berry aneurysm tend to affect the parasympathetic fibers 1st resulting in a dilated pupil [mydriasis] and suppression of papillary light reflex.
Complete lesion results most dramatically in an inability to adduct eyeball.
Pxs may have external strabismus [laterally deviated eyeball] that results from unopposed contractions of lateral rectus and superior oblique.
It may also result in ptosis; w/c is due to weakness of skeletal motor part of levator palpebrae superioris muscle.
Trochlear N. lesions
Results in diplopia, when a px attempts to depress the adducted eye. Pxs may experience difficulty in reading or difficulty in going down the stairs.
They may tilt their head away from side of the leioned nerve w/c resuts from weakness in the ability to rotate the affected eyeball inward [intorsion]. The head tilt is an attempt to counteract the extorsion by the unopposed inferior oblique and inferior rectus muscles.
A head tilt observed in pxs w/ trochear nerve lesion might be mistaken for torticollis caused by abnormal contractions of sternocleidomastoid muscle.
Abducens N. lesions
Result in weakness in the ability to fully abduct the eye. The superior and inferior oblique muscles act to partially abduct the eye. Pxs may have internal strabismus [medially deviated eyeball] because of the unopposed contractions of medial rectus muscle and other adductors innervated by CN 3.
Abducens nerve is MC the 1st nerve to be affected in a thrombosis of cavernous sinus. Hypoglossal N. lesions
Result in deviation of tongue towards side of the injured nerve on protrusion. They may experience dysarthria and difficulty moving a bolus of food from the oral cavity into the oropharynx.
Facial N. reflexes
Blink reflex uses sensory fibers of the ophthalmic division of CN 5 and skeletal motor fibers of facial N. [CN 8]. Causes direct and consensual blink that results from bilateral contraction of orbicularis oculi muscles.
Lacrimal reflex also uses sensory fiber of CN V1 and results in an increase in lacrimal secretions in response to touching the cornea or in response to chemical stimulants.
Taste salivary reflex, stimulation of taste receptors on the anterior 2/3 of tongue may cause an increase in salivary gland secretions.
Facial N. lesions
Occur in facial canal and result in Bell’s palsy. Pxs manifest w/ weakness of muscles of facial expression on side of injured nerve. There is weakness in the ability to shut the eye, nasal flaring, and wrinkle the forehead. There is also drooping of corner of the mouth. They may have pain behind the external auditory meatus resulting from involvement of the general sensory fibers of the posterior auricular nerve.
Lesions of facial N. at genicuate ganglion may have alterations in taste sensations [from anterior 2/3 of tongue and palate], a reduction in salivary gland secretions [from submandibular and sublingual glands] and a dry eye [from a reduction of lacrimal secretions].
Hyperacusis [hypersensitivity to loud sounds] may result if nerve to stapedius is affected. As pxs recover from a facial nerve lesion, they may experience synkinesis, w/c results from
misdirected regenerating motor axons.
Distal to stylomastoid foramen, a tumor of the parotid gland may compress muscular branches of facial N. as they traverse the gland and may result in a weakness of muscles of facial expression but no sensory deficits, hyperacusis or alteration of glandular secretions.
SPINAL NERVES
Consists of 31 pairs [8 cervical, 12 thoracic, 5 lumbar, 1 coccygeal] Formed by union of dorsal root and ventral root at intervertebral foramen Other components:
At T1-L2, trunk of spinal nerve contains preganglioninc symphathetic fibers from cell bodies in the intermediolateral cell column of spinal cord
At S2-4, trunk and proximal ventral rami contain preganglioninc parasymphathetic fibers from cell bodies in sacral parasymphathetic nucleus of spinal cord. They leave the ventral rami as pelvic splanchnic nerves [nervi erigentes]
AUTONOMIC NERVOUS SYSTEM
Innervates visceral organs [vascular, glandular], motor to cardiac, smooth muscles and glands, it also maintains homeostasis
Above and below T1 to L2-3 levels of spinal cord, there are no more white rami.
Divisions Features
Symphathetic NS Activates body’s response to stress [fight or flight reponse] Parasymphathetic NS
[rest or digest]
Also called craniosacral flow [from S2-4 spinal cord], part of CN 3,7,9,10, supplies cardiac, smooth and glands but does not innervate blood vessels [except erectile tissue of ext. genitalia] Autonomic nerve functions:
Features Sympathetic Parasympathetic
SA node Increases HR Decreases HR
AV node ↑ conduction delay ↓ conduction delay
Cardiac output ↑ contractility and velocity of
conduction ↓ contractility and velocity of conduction Blood vessels Generally constricts Generally dilates Skin, mucosa, salivary glands Generally constricts Little effect Radial muscle of iris Dilates pupil; mydriasis
-Sphincter muscle of iris - Constricts pupil; miosis
Ciliary muscle Relaxes for far vision Contracts Trachea, bronchi, lungs Relaxes, allows dilation Constricts Gastrointestinal structures Inhibits Stimulates peristalsis Internal anal sphincter Contributes to contraction Contributes to relaxation
Urinary bladder Inhibits Contracts
Uterus Variable Variable
Arrector pili muscles Contracts No effect
Salivary glands ↑ viscosity of secretion Stimulates secretion Lacrimal gland, nasal glands No direct effect Stimulates secretion
Gastrointestinal glands Inhibits Stimulates
Sweat glands Stimulates secretion
-Adrenal medulla Simulates secretion
-Pineal gland Increases synhesis and
release of melatonin
-Erection - Facilitates
Secretion No direct effect Facilitates
Emission Facilitates No direct effect
Clinical notes Horner’s syndrome
Lesion in either preganglionic or postganglionic sympathetic neurons that innervate sweat glands and blood vessels in face and scalp or 2 smooth muscles in the orbit. The smooth muscle elevates the upper eyelid and dilates the pupil.
S/Sx: anhydrosis [inability to sweat on corresponding side of the face], ptosis [drooping of upper eyelid], miosis [pupil constriction]
Shy-Drager syndrome
Degeneration of preganglionic sympathetic and parasympathetic neurons in brainstem and spinal cord and degeneration of neurons in most ganglia. This may be combined w/ loss of other non-autonomic CNS neurons.
S/Sx: impotence, urine retention, dizziness on standing, blurred vision, and inability to sweat. Hirschprung’s disease [aganglionic megacolon]
Failure of neural crest cells either to migrate into the wall of descending colon, sigmoid colon, or rectum or to differentiate into terminal parasympathetic ganglia in these areas.
It results in absence of perisalsis in the affected segment and a distended bowel proximal to that segment.
Reflexes – autonomic motor response to a sensory stimulus, examples include: Muscle stretch
reflexes Muscle spindles in skeletal muscles are stimulated by stretch causing a reflex contraction of that same muscle Autonomic
reflexes Sensory stimuli cause reflex contraction of smooth muscle, the secretion of a gland, or a change in rate and force of contraction of cardiac muscle Cranial nerve
reflex Use sensory and motor fibers in 1 or more cranial nerves and include papillary light reflex, blink reflex, gag reflex, and cough reflex. Clinical notes
Reduced sensation [hypesthesia] and altered sensation [paresthesia] are sensory signs. Weakness [paresis] of skeletal muscles is a motor sign.
Nerve lesions are destructive when nerves are severely compressed or severed, resulting in a loss of abiity of nerves to conduct impulses.
Lesions to sensory fibers result in loss of sensory modality or modalities carried by fibers in that nerve [anesthesia].
Lesions to motor fibers result in paralysis of denervated skeletal muscles. Denervated skeletal muscle fibers exhibit fasciculations [random twitches seen beneath skin] and may atrophy. CHAPTER 2 – UPPER EXTREMITY
AXILLA, PECTORAL REGION AND SHOULDER [refer to Neter p. 400] Boundaries of the axilla
Base: axillary fascia and skin of armpit
Apex: clavicle anteriorly, 1st rib medially, superior border of scapula posteriorly Medial wall: upper rib cage
Lateral wall: intertubercular groove
Anterior wall: pectoralis major and minor muscle
Posterior wall: subscapularis, teres major and latissimus dorsi muscles Boundarie
s Quadrangular space Triangular space
Lateral Surgical neck of humerus Shaft of humerus Medial Long head of triceps brachii Long head of triceps brachii Superior Teres minor, subscapularis Teres major
Inferior Teres major None
Quadralateral space
Above: subscapularis [front], teres minor behind] Below: teres major
Lateral: surgical neck of humerus Medial: long head of triceps
Contents: passage for axillary joint Axillary lymph nodesName Distribution
Lateral/ brachial nodes Upper extremity except vessels following cephalic vein Posterior/ subscapular nodes Shoulder, trunk, lower neck
Pectoral/ anterior nodes Breast and anterior chest wall
Central nodes Receives lateral, posterior and pectoral nodes Apical nodes Receives lymph from all other groups Bones of upper extremities [refer to Netter p. 391-392, 407, and 426]
Division Type Features
Pectoral girdle and proximal humerus
Clavicle or
collar bone MC fractured at middle and lateral third. Only bone to undergo intramembranous ossification, 1st to ossify 5-6 wks Scapula or
shoulder blade Overlies 2 nd-7th ribs
Articulates w/ clavicle and humerus
Skeleton at
elbow Distal humerusProximal radius Proximal ulna
Accounts for carrying angle in the elbow Where biceps brachii tendon attaches Where triceps brachii tendon attaches Skeleton of wrist and hand Distal radius Distal ulna Phalanges Metacarpals [5] Carpal bones [8]
w/ dorsal tubercle of LISTER for ext. pollicis longus For articulation w/ articular disc
2 for thumb, 3 for fingers, forms the knucles 2nd metacarpal is the longest
Pisiform – last to ossify [10-12 yrs], capitate – 1st to ossify [2-3 mos.] – Some Lovers Try Position That They Can’t Handle Proximal [lat-medial] – scaphoid, lunate, triquetrum, pisiform Distal [lat-medial] – trapezium, trapezoid, capitate, hamate Clinical notes
Clavicular fracture
Commonly fractured at its weakest point between middle third and lateral third.
Middle 2/3 may be elevated by sternocleidomastoid and lateral 3rd may be depressed by weight of the limb or adducted by petoralis major.
The ventral rami of C8-T1 in medial cord of brachial plexus may be lacerated due to fracture. Shoulder trauma to acromioclavicular joint
May be caused by subluxation of aromion at the acromioclavicular joint. The coracocavicular ligament w/c extends from the acromion, prevents dislocation at acromioclavicular joint. Colle’s fracture
Fracture at distal radius may result in avulsion of styloid process from shaft of radius. May exhibit “dinner-fork deformity” as a result of the posterior displacement of the distal radius. Lunate dislocation
MC dis L ocated carpal bone. Typically dislocated anteriorly into the carpal tunnel. This may cause carpal tunnel syndrome.
Scaphoid fracture
MC fractured carpal bone
S/Sx: pain and tenderness localized over anatomic snuffbox. The proximal part of scaphoid may undergo vascular necrosis because blood supply to bone supplies distal part first then proximal. Joints of upper extremity
Name of joint Type Features
Sternoclavicular Ball and socket Only joint btw trunk and upper limb Acromioclavicular Atypical synovial Dislocated w/ fall on outstretched hand Shoulder
[glenohumeral] Ball and socket Supplied by axillary, suprascapular, lat. Pectoral nerves, joins upper extremity to pectoral girdle Elbow Synovial hinge Strengthened by medial and lateral collateral ligament Prox’l radioulnar
Distal radioulnar Synovial pivot types of joint Annular lig. - Chief ligament of proximal radioulnar jt. Distal radioulnar jt - provide the strongest attachment Joints of wrist and hand
Name of joint Type Features
Radiocarpal Condyloid Does not includes the ulna or pisiform bones Midcarpal Plane / ellipsoid Allows flexion, extension, abduction and adduction Carpometacarpal Saddle type [1st] Flexion, extension, abduction, adduction, opposition Metacarpophalangeal Condyloid Flexion, extension, abduction, adduction, rotation Interphalangeal Hinge Allows only flexion and extension
Veins of upper extremity [refer to Netter p. 400]
Location Name of vein Distribution Drainage
Superficial Dorsal venous arch Back of hand Cephalic [lateral] and basilic [medial] veins Cephalic veins Lateral forearm Axillary vein
Basilic veins Medial forearm Axillary vein
Median cubital Cubital fossa Connects cephalic to basilica vein Median antebrachial Middle forearm
Deep veins Axillary vein
[brachial + basilic] Main venous structure draining the upper extremity, it becomes the subclavian vein at outer border of 1st rib Arteries of upper extremity [refer to Neter p. 398, 435]
Name of artery Features
Subclavian A. Branch: thyrocervical trunk w/c divides into:
Suprascapular A.
Transverse cervical A. – deep branch gives rise to dorsal scapular A. Axillary A.
[shoulder] 1
st part – gives rise to superior or highest thoracic A. 2nd part – gives rise to thoracoacromial and lateral thoracic A.
3rd part – gives rise to subscapular [largest branch], anterior and posterior
humeral circumflex
Brachial A. [arm] Branches: profunda brachii, superior and inferior ulnar collateral arteries,
muscular, nutrient A. to humerus
Radial A. [forearm] Branches: radial recurrent A., muscular and superficial palmar branch, 1st
dorsal metacarpal branch, arteria princes pollicis, arteria radialis indicis
Ulnar A. [forearm] Branches: anterior and posterior ulnar recurrent, the common, anterior and
posterior interosseous, deep palmar arch [palmar, metacarpal, perforating br.]
Scapular anast. Joins axillary system w/ subclavian system
Wrist & arm anast. Joins branches of radial & ulnar A. Lymphatic drainage of upper limb
Name of nodes Features
Axillary LN Drains from entire upper limb , located as follows: anterior pectoral, posterior subscapular, lateral, infraclavicular/deltopectoral and apical LN
Supratrochlear LN Aka cubital LN which drains from medial fingers, medial arm and forearm Clinical notes
Volkmann’s ischemic contracture
Caused by supracondylar fracture of humerus w/c compress brachial A. resulting in ischemia of forearm &hand. The hand is flexed at wrist & fingers are flexed at the interphalangeal joints.Dupuytren’s contracture
Caused by fibrosis and shortening of palmar aponeurosis. Thickening and shortening of the bands of aponeurosis over the flexor tendons results in flexion of ring and little fingers. Brachial plexus [from ventral rami of spinal nerves C5-T1]Branch Name Distribution
Lateral cord Lateral pectoral [C5-7] Pectoralis major and minor muscles Medial cord Medial pectoral [C8, T1]
Medial brachial cutaneous [C8-T1] Medial antebranchial cutaneous
Pectoralis major and minor muscles Skin on medial aspect of arm Skin of forearm
Posterior Upper subscapular [C5-6] Thoracodorsal [C6-8] Lower subscapular [C5-6]
Subscapularis, upper part Latissimus dorsi Subscapularis, lower part Terminal branches of brachial plexus
Name Features Origin
Musculocutaneous [C5-7] Supplies coracobrachialis, brachialis, biceps brachii Lateral Axillary [C5-6] Supplies deltoid, teres minor and major muscles Posterior Radial [C5-8, T1] Largest branch of brachial plexus and is the
sole innervation of extensor compartments of arm and forearm, supplies most of the cutaneous innervations to back opf arm, forearm and hand
Posterior
Ulnar [C8, T1] Main nerve to small muscles of the hand Medial
Median [C5-8, T1] Branch:
Anterior interosseous nerve
Supplies all muscles in anterior forearm [except flexor carpi ulnaris and ulnar half of flexor digitorum longus – ulnar N., brachioradialis – radial N.], also supplies thenar muscles and lateral 2 lumbricals
Supplies flexor pollicis longus, lateral half of flexor digitorum profundus and pronator quadratus Muscles of pectoral girdle and shoulder
Muscles that move shoulder girdle
Name Innervation
Trapezius Accessory N. [motor], C3-4 [sensory] Latissimus dorsi Thoracodorsal N.
Rhomboid major and minor Dorsal scapular N.
Levator scapulae Dorsal scapular N. [motor], C3-4 [sensory]
Serratus anterior Long thoracic N.
Pectoralis minor Medial pectoral N.
Subclavius Nerve to subclavius [upper trunk of brachial] Rotator [musculotendinous] cuff muscles – major stabilizing factor for shoulder joint
Name [from top – SITS] Innervation
Supraspinatus Suprascapular N.
infraspinatus Suprascapular N.
Teres minor Axillary N.
Subscapularis Upper and lower subscapular N. Other muscles that move the humerus
Name Innervation
Pectoralis major Lateral pectoral N.
Deltoid Axillary N.
Latissimus dorsi Thoracodorsal N. Teres major Lower subscapular N. Clinical notes
Inflammation of Rotator cuff
Tendon of supraspinatus is most commonly affected.
Pxs w/ rotator cuff tears experience pain anterior to glenohumeral joint during abduction. Humeral dislocation
Head of humerus is commonly displaced inferiorly then anteriorly and becomes positioned just inferior to coracoid process. This may stretch the axillary or radial nerve.
Humeral fracture
In a fracture of the surgical neck of humerus, axillary neve may be lesioned, and posterior circumflex artery may be lacerated.
Fracture on the greater tubercle of humerus may result in avulsion of greater tubercle and detachment of the rotator cuff muscles from humerus.
A transverse fracture of humerus distal to deltoid tuberosity may result in abduction of proximal fragment by deltoid muscle.
In a midshaft spinal fracture of humerus, the radial nerve may be lesioned and the profunda brachii artery may be lacerated.
In supracondylar fracture of humerus, contraction of triceps and brachialis may shorten the arm. Median nerve may be lesioned as a result of an intercondylar or supracondylar fracture of the distal end of humerus.
In fracture of medial epicondyle of humerus, the ulnar nerve may be lesioned. Epicondylitis
LaTEral epicondyitis [TEnnis elbow] – infammation of common extensor tendon that results from forced extension and flexion of the forearm at the elbow. Pxs exhibit pain over the lateral epicondyle w/c may radiate down the posterior aspect of forearm.
Medial epicondylitis [golfer’s elbow] – inflammation of common flexor tendon that results from repetitive flexion and pronation of forearm at elbow.
ARM AND FOREARM
Cubital fossa [refer to Netter p. 402]
bounded by: brachioradialis [lateral], pronator teres [medial], brachialis and supinator [floor], skin, fascia and bicipital aponeurosis [roof]
Medial to lateral contents: median N., fats, brachial A. bifurcation, biceps tendon, radial and ulnar A, radial N.
crossed superficially by median cubital V. [for phlebotomy] Muscles of the Upper Arm [refer to Netter p. 403]
Name Innervation Actions
Coracobrachialis Musculocutaneous N. Flex and adduct arm Brachialis Musculocutaneous N. Flex elbow joint
Biceps brachii Musculocutaneous N. Flex elbow joint, supinates forearm
Triceps brachii Radial N. Extends elbow joint
Anconeus Radial N. Extends elbow joint
Muscles of flexor compartment of forearm [refer to Netter p. 402 & 416]
Name Innervation Actions
Superficial group
Pronator teres Median nerve Pronates forearm Flexor carpi radialis Median Flex and adducts hand
Palmaris longus Median Flex hand
Flexor digitorum superficialis Median Flexes PIP Flexor carpi ulnaris Ulnar nerve Flex and adducts hand Deep group
Pronator quadratus Median Pronates forearm
Flexor pollicis longus Median Flex interphlangeal joint of thumb Flexor digitorum profundus Ulnar nerve Flexes DIP
Muscles of extensor compartment of forearm [refer to Netter p. 403 & 414]
Name Innervation Actions
Superficial group
Brachioradialis Radial Flex elbow
Extensor carpi radialis longus Radial Extends and abducts hand Ext. carpi radialis brevis Radial Extends and abducts hand Extensor digitorum Radial Extends phalanges and wrist Extensor digiti minimi Radial Extends 5th finger Extensor carpi ulnaris Radial Extends and abducts hand Deep group
Supinator Radial Supinates forearm
Abductor pollicis longus Radial Abducts thumb Extensor pollicis brevis Radial Extend thumb Extensor pollicis longus Radial Extends thumb Extensor indicis Radial Extend index finger WRIST AND HAND
Carpal tunnel
Formed poseriorly by 8 carpal bones.
Contents: median nerve, flexor digitorum superficialis & profondus, flexor pollicis longus. Phalen’s test – dorsal surface of both hands pressed together w/ wrist flexion produces
pain
Canal of Guyon
Located btw pisiform and hook of hamate superficial to carpal tunnel. The ulnar nerve, ulnar artery, and ulnar vein cross the wrist and pass into the hand after traversing the canal. Anatomic snuffbox [refer to Netter p. 434]
Lateral: tendons of abductor pollicis longus and extensor pollicis brevis Medial: extensor pollicis longus
Floor: scaphoid and trapezium Contents: radial artery
Its skin is innervated by superficial branch of radial nerve Thenar muscles
Name Innervation Actions
Abductor pollicis brevis Median N. Abducts thumb
Flexor pollicis brevis Median N. Flex metacarpophalangeal jt. Thumb Opponens pollicis Median N. Opposes thumb to other digits Adductor pollicis Ulnar N. Adducts thumb
Hypothenar muscles
Name Innervation Actions
Abductor digiti minimi Ulnar N. Abducts little finger
Flexor digiti minimi brevis Ulnar N. Flexes metacarpophalangeal jt [LF] Opponens digiti minimi Ulnar N. Opposes little finger to thumb, helps in
cupping the palm Palmaris brevis Ulnar N. Tenses skin on medial palm Interosseus and lumbrical muscles
Name Innervation Actions
Palmar interossei [3] Ulnar N. Adduct fingers, flex metacarpal jts Dorsal interossei [4] Ulnar N. Abduct fingers, flex metacarpal jts Lumbricals [4] Medial [1,2] - ulnar
Lateral [3,4] – median Flexes metacarpophalangeal jts., extend interphalangeal jts NOTE: C6 dermatome – thumb, C8 – little finger
Arteries of hand
Name Branches
Radial A. Dorsal digital A., princeps pollicis A., radialis indicis A.
Ulnar A. Deep palmar and superficial palmar arch
Dorsal carpal arch 3 dorsal metacarpal A., dorsal digital A.
Thenar & midplamar spaces
Thenar space Contents: 1st lumbrical, long flexor tendon [thumb and index finger]
Midpalmar space Contents: lumbricals, long flexor tendons of medial 3 fingers Nerve injuries of upper extremities [refer to Netter p. 441]
Injury Affected Causes Manifestations
Erb-duchenne
palsy – upper C5-6 spinal n. [superior trunk] Violent fall on shoulder [ex. motorcycle], birth injury Waiter’s tip hand Klumpke’s
paralysis - lower C8-T1 spinal n. [inferior trunk] All from a height, birth injury Clawhand or ape-hand deformity [cannot fist] Thoracodorsal N. Latissimus dorsi Improper use of crutch, [+]
difficulty in elevating trunk Crutch palsy or Saturday night palsy Long thoracic N. Serratus anterior Paralysis of serratus
anterior, can’t abduct above the horizontal
Winged scapula Musculocutaneous
nerve Biceps and brachialis Waiter’s tip hand
Axillary nerve Deltoids Fracture of surgical neck of humerus or inferior dislocation of shoulder jt.
Crutch pressure injury Radial nerve Extensors of
wrist and fingers Improper deltoid injection or tight cast, Wristdrop Median nerve [recurrent branch] Thenar nuscles, lateral 2 fingers, lumbricals
Numb palm and finger, inability to flex fingers, in typist, as in Dupuytren’s
Papal benediction & forearm ‘ape-like hand’ Carpal tunnel syndrome Ulnar nerve Medial 2
lumbricals Inability to adduct/abduct fingers, interosseous atropy Ulnar Clawhand
Suprascapular N. Waiter’s tip position
Spinal accessory Drooping of shoulder
RAPID REVIEW
Muscles of the flexor forearm compartment NOT supplied by median nerve are the: flexor carpi ulnaris and ulnar half of flexor digitorum longus [w/c are supplied by ulnar nerve] The only THENAR muscle NOT supplied by median nerve is the adductor polis [w/c
is supplied by ulnar nerve]
Not strictly a thenar muscle – adductor pollicis muscle
All interosseus and lumbrical muscles are supplied by ulnar nerve EXCEPT the lateral 2 lumbricals [w/c are supplied by median nerve]
musculocutaneous n. – main branch of the lateral cord radial n. – biggest branch of brachial plexus hearT-shaped vertebra = Thoracic kidney-shaped vertebra = lumbar Brachioradialis
Function: “beer raising muscle”, flexes the elbow Strongest when writ is oriented like holding a beer Innervation: it’s a flexor muscle but innervated by radial nerve The only flexor muscle supplied by radial nerve [radial nerve usually supplies the extensors] CHAPTER 3 – LOWER EXTREMITY
Bones of lower extremities
Division Type Features Pelvic
girdle Pubis Ilium Forms the anterior and medial part of hipboneForms the lateral part of hipbone Ischium Posterior and inferior part of hipbone Acetabulum Formed by ilium, ischium and pubis
Femur w/ fovea capitis [ligament of head], quadrate tubercle [quadratus femoris] Patella Largest bone to develop w/in tendon of a muscle , a sesamoid bone Tibia Weight-bearing bone of the leg, w/tibial tubrosity [patellar ligament] Fibula Non-weight bearing bone of the leg, w/ interosseous border Joints of the lower extremities
Sacroiliac joint Synovial Only joint btw pelvic girdle and axial skeleton Hip joint Ball and socket Strengthened by 3 ligaments: iliofemoral [strongest],
pubofemoral, and ischiofemoral lig.
Knee joint Modified hinge jt Located btw patella and femur, formed by lateral and medial condyles of femur and tibial plateus
Ankle joint Synovial hinge jt Include the talocrural, subtalar, and transverse tarsal joints Ligaments of the lower extremity
Name Features
Iliofemoral Strongest and most important ligament of the hip joint Ischiofemoral Thinnest of the ligaments of hip joint
Pubofemoral Resists excessive abduction of hip joint Patellar ligament Anterior ligament of knee joint Tibial collateral Important stabilizer of knee joint
Fibular collateral Is taut and stabilizes the joint best when knee if fully extended Anterior cruciate Maximally taut and stabilizes the joint best w/ fully extended knee Posterior cruciate Maximally taut and stabilizes the joint best w/ fully extended knee Menisci of knee joint Shock absorbers, lateral meniscus is more movable
Clinical notes Fracture of Femoral neck
The head of femur may undergo avascular necrosis as a result of disruption of the branches of medial circumflex femoral artery [main source of arterial supply to head & neck of femur] In pxs w/ fractures of the femoral neck, the thigh is laterally rotated by the short lateral rotators of
the thigh at the hip and the gluteus maximus. Dislocation of femoral head
This most commonly occur in posterior direction. The thigh is shortened and medially rotated by gluteus medius and minimus muscles.
The sciatic nerve may be compressed, resulting in weakness of muscles in the posterior thigh, leg, and foot, and paresthesia over the posterior and lateral parts of the leg and the dorsal and plantar surfaces.
Knee injuries
The 3 most commonly injured structures at the knee are the tibial collateral ligament, medial meniscus and ACL [the terrible triad].
A blow to lateral apect of knee when foot is on the ground may sprain the tibial collateral ligaments; the medial meniscus may also be torn.
ACL tears may occur when tibial collateral ligament and medial meniscus are injured; a blow to the anterior aspect of the flexed knee may tear only ACL.
Pxs w/ a torn ACL exhibit an anterior drawer sign, in w/c tibia may be displaced anteriorly from the femur in the flexed knee.
Ankle sprains
Inversion ankle joints are more common than eversion sprains at the talocrural joint. The anterior talofibular part of the lateral ligament is commonly torn in inversion ankle sprains.
Veins of lower extremity
Location Name of vein Distribution Drainage
Superficial Dorsal venous arch Dorsum of foot Small + great saphenous V. Small saphenous Posterior leg Popliteal vein
Great saphenous Anterior leg Popiteal Deep veins Venae comitantes Paired, runs alongside of arteries
Femoral vein Main venous structure draining the lower extremity Arteries of lower extremity
Name Origin Branches
Femoral A. External iliac A. Superficial circumflex iliac, superficial epigastric,
superficial and deep external pudendal, profunda femoris and descending genicular arteries
Popiteal A. Femoral A. Muscular br., articular br. to knee joint, terminal
branches [anterior and posterior tibial arteries]
Anterior tibial A Popliteal A. Muscular and anastomotic branches
Dorsalis pedis Anterior tibial A. Lateral tarsal, arcuate & 1st dorsal metatarsal A.
Posterior tibial Popliteal A. Peroneal, nutrient A. to tibia, medial & lateral
plantar, muscular branches & anastomotic branches
Internal iliac A. Common iliac A. Superior & inferior gluteal, and obturator artery
Clinical notes
Cruciate anastomosis in posterior thigh is formed by medial and lateral circumflex femoral A., inferior gluteal A. and 1st perforating A. This may contribute to collateral circulation of lower limb if femoral artery becomes occluded.
Anastomosis around knee joint is formed by descending genicular A. [from femoral A.], lateral femoral circumflex A. [from profunda femoris], articular branch [from popliteal A.], and branches from anterior and posterior tibial A.
Dorsalis pedis pulse may be evaluated by compressing the dorsal artery of foot against tarsal
bones lateral to tendon of extensor hallucis longus. Nerves of lower extremity
Name of nerve Features Lumbosacral
plexus Formed by ventral rami of L4 thru S3. The posterior and anterior division form 2 terminal nerves: common peroneal/fibular N., and tibial N. Lumbosacral trunk Formed by fibers of L4 and L5
Terminal nerves of the lumbar plexus
Name Component
s Features
Femoral N. L2-4 Largest branch of lumbar plexus, w/ cutaneous br. [gives rise to saphenous N., medial and intermediate cutaneous N. of thigh] , muscular br. & articular branches., susceptible to injury
Saphenous Femoral N. Only branch of femoral N. to extend below the knee Obturator N. L2-4 Branches: anterior, posterior, and articular branches Clinical notes
Femoral N. lesions
The femoral nerve may be damaged in the abdomen by an abscess of the psoas major. Pxs experience weakness in the ability to flex thigh at the hip, weakness in the abiity to extend the leg at the knee, and a diminished patellar tendon reflex.
Saphenous N. lesions
Saphenous nerve may be lesioned during a surgical procedure of the leg to remove part of the great saphenous vein, or it may be lacerated as it pierces the wall of adductor canal. Pxs experience pain and paresthesia in the skin of the medial aspect of leg and foot.
Obturator N. lesions
Obturator nerve is commonly lesioned in the pelvis. Pxs are unable to adduct the thigh at he hip and may have paresthesia in skin of the medial thigh.
5 collateral nerves of lumbar plexus Name of nerve Features
Subcostal nerve Innervates abdominal musculature & skin of lateral & anterior abdominal wall iliohypogastric N. Innervates abdominal musculature and skin of inguinal and hypogastric
regions of the lateral and anterior abdominal wall
iIioiguinal N. Innervates the skin of the medial thigh, labium majus, and anterior scrotum Genitofemoral N. Innervates skin on medial thigh [femoral br.], & cremasteric M. [genital br.] Lateral femoral
cuaneous N.
Inervates the skin of the lateral thigh Clinical notes
Lateral femoral cutaneous nerve lesions
The lateral femoral cutaneous nerve may be compressed as it passes posterior to lateral part of inguinal ligament just medial to anterosuperior iliac spine. Pxs w/ compression of the lateral femoral cutaneous nerve [meralgia paresthetica] present w/ pain and paresthesia in the anterolateral thigh.
Terminal branches of lumbosacral plexus Name of nerve Features
Sciatic nerve Largest branch of lumbosacral plexus, largest nerve of the body, branches: tibial and common peroneal N.
Superior gluteal N Innervates gluteus medius and minimus, tensor fasciae latae Inferior guteal N. Innervates gluteus maximus muscle
Tibial N. Principal nerve to posterior thigh and leg, sole of foot, divides into medial plantar N. [w/c innervates flexor digitorum brevis, flexor hallucis brevis, abductor hallucis and 1st lumbrical] and lateral plantar N. [w/c innervates skin of lateral side of the sole of foot and lateral ½ digits.
Common fibular /
peroneal nerve Innervates the short head of biceps femoris, divides into superficial and deep fibular N. as it enters he fibularis longus muscle. Superficial fibular Innervates the fibularis longus and brevis muscles
Deep fibular N. Innervates tibialis anterior, extensor hallucis longus, extensor digitorum longus, and peroneus tertius muscle
Clinical notes
Superficial gluteal N. lesions
This pxs have weakness in the ability to abduct the thigh at the hip. They experience a “waddling or trendelenburg gait”, in w/c the pelvis sags on side of the unsupported limb.
Inferior gluteal N. lesions
This pxs have a weakness in the ability to laterally rotate and extend the thigh at the hip. They have difficulty extending the thigh at the hip from a flexed position as in climbing the stairs or
rising from a chair.
Pxs may have a gluteus maximus gait in w/c they thrust their torso posteriorly in an attempt to counteract the weakness of the gluteus maximus.
Sciatic N. lesions
Susceptible to damage from an IM injection in the lower medial quadrant of gluteus maximus muscle, or it may be compressed as a result of posterior dislocation of the femur. “Foot drop” – all muscles of the knee are paralyzed due to sciatic nerve lesion. Common fibular N. lesions
It is the most frequently lesioned nerve in lower limb. This usually occurs as it passes around neck of fibula.
Pxs experience “foodrop” w/c results from a loss of dorsifexion at the ankle and loss of eversion. They also have pain and paresthesia in the lateral leg and dorsum of the foot.
Pxs w/ foodrop may have “steppage gait” in w/c they raise their affected leg high off the ground and their foot slaps the ground when walking.
In piriformis syndrome, the common fibular nerve may be compressed by fibers of the piriformis muscle when the nerve passes thru the piriformis rather than anterior to it w/ tibial N.
Superficial fibular N. lesions
The nerve may be lesioned as he nnerve emerges from lateral compartment of the leg. Pxs experience pain and paresthesia in the dorsal aspect of the foot.
Deep fibular N. lesions
The nerve may be compressed in the anterior compartment of the leg. This pxs may have footdrop and parethesia in skin of the webbed space btw the great toe and 2nd toe.
Lymphatics of lower extremity
Name Distribution
Superficial inguinal nodes Receive lymph from thigh, foot, leg, buttock, perineum Deep inguinal nodes Receive lymph from deep structure of thigh and leg Popliteal LN Receive lymph from deep structures of leg below the knee GLUTEAL REGION
Important features of gluteal region
Sacrotuberous lig. Connects posterior iliac spines, sacrum, coccyx to ischial tuberosity Sacrospinous lig. Connects posterior surface of sacrum and coccyx w/ ischial spine Greater sciatic
foramen Transmits: piriformis M., sciatic N., superior and inferior gluteal N. andvessels, pudendal N., internal pudendal A and V, posterior femoral cutaneous N, nerve to quadratus femoris and obturator internus Lesser sciatic
foramen Transmits: tendon of obturator internus, nerve to obturator internus, pudendal nerve, internal pudendal artery and vein Muscles of gluteal region [refer to Netter p. 461]
Name Innervation Actions
Gluteus maximus Inferior gluteal N. Extends, laterally rotates thigh Gluteus medius Superior gluteal N Abducts and medially rotates thigh Gluteus minimus Superior gluteal N Abducts and medially rotates thigh Tensor fasciae latae Superior gluteal N Flex, abducts,medially rotates thigh Piriformis S1-2 lumbar plexus Laterally rotates thigh
Obturator internus N. to obturator internus Laterally rotates thigh Superior gemelli N. to obturator internus Laterally rotates thigh Inferior gemelli N. to quadratus femoris Laterally rotates thigh Quadratus femoris N. to quadratus fwmoris Laterally rotates thigh Vessels of gluteal region
Name Features
Superior gluteal A. Largest branch of internal iliac A., w/ superior and inferior branches
Inferior gluteal A. Gives rise to companion artery to sciatic nerve
Internal pudendal A. Distributed to perineum, no branches to gluteal region
THIGH
Important features of thigh
Fascia lata Deep investing fascia of lata, acts like a tight stocking Iliotibial tract Important in maintaining posture and in locomotion
Saphenous opening Aka fossa ovalis, transmits great saphenous V. & superficial femoral A Femoral sheath Derived from transversalis fascia. Lateral-medial: invests the femoral A,
femoral V, and femoral canal
Femoral canal Most medial compartment of femoral sheath, a potential weak area Femoral ring Lacunar ligament [medial], femoral V [lateral], inguinal ligament [anterior],
superior ramus of pubis and pectineal ligament [posterior]
Femoral triangle Sartorius [lateral], Adductor longus [medial], iliopsoas and pectineus [floor] & Inguinal Ligament [base] - SAIL
Contents: femoral N, A, V., inguinal LN, femoral sheath Adductor canal of
Hunter or subartorial canal
Lies btw vastus medialis, adductor brevis and magnus, covered by sartorius muscle [thus called subsartorial canal]
Contents: femoral A + V, saphenous N., nerve. to vastus medialis, LN Cruciate anastomosis Provides an important potential collateral pathway to bypass an obstruction
of external iliac or femoral artery Profunda femoris A Largest branch of femoral artery Perforating arteries Major supply to posterior thigh Muscles of posterior thigh [refer to Netter p. 461]
Name Innervation Actions
Semitendinosus Tibial division of sciatic Extends thigh, flex knee, rotates leg medially Semimembranosus Tibial division of sciatic Extends thigh, flex knee, rotates leg medially Biceps femoris Long head: sciatic N.
Short: common peroneal Extends thigh, flex knee, rotates leg laterally Muscles of anterior thigh [refer to Netter p. 458]
Name Innervation Actions
Iliacus Femoral N. Flex thigh
Psoas major Ventral rami [L2-3] Flex thigh
Sartorius Femoral N. Flex and laterally rotates thigh, flex knee joint Rectus femoris Femoral N. Flex thigh, extend knee joint
Vastus medialis Femoral N. Extends knee joint Vastus lateralis Femoral N. Extends knee joint Vastus
intermedius Femoral N. Extends knee joint
Articularis genus Femoral N. Retracts synovial membrane on extended knee Muscles of medial thigh [refer to Netter p. 459]
Name Innervation Actions
Pectineus Femoral and obturator Flex and adducts thigh Obturator externus Obturator N. Laterally rotates thigh
Gracilis Obturator N. Adducts thigh, flex and medially rotates knee Adductor longus Obturator N. Adducts and laterally rotates thigh Adductor brevis Obturator N. Adducts and laterally rotates thigh Adductor magnus Adductor part: obturator
Hamstring: sciatic N. Adductor part: adducts and lat rotates thighHamstring: extends thigh Vessels of thigh
Name Branches
Femoral artery Superficial epigastric, superficial circumflex iliac, superficial + deep
external pudendal, profunda femoris [largest branch], medial + lateral femoral circumflex, perforating arteries, descending genicular arteries
Obturator artery Anterior and posterior branches
LEG AND POPLITEAL REGION
Muscles of the anterior and lateral compartments of the leg [refer to Netter p. 484]
Name Innervation Actions
Anterior group
Tibialis anterior Deep peroneal Dorsiflex ankle, inverts foot Extensor digitorum longus Deep peroneal Extends toes, dorsiflex foot Extensor hallucis longus Deep peroneal Extends great toe, dorsiflex foot Peroneus tertius Deep peroneal Dorsiflex ankle and everts foot Deep group
Peroneus longus Superficial peroneal Everts foot Peroneus brevis Superficial peroneal Everts foot Muscles of the posterior compartment of the leg [refer to Netter p. 482]
Name Innervation Actions
Superficial group
Soleus Tibial N. Plantar flex foot
Gastrocnemius [medial ,lateral] Tibial Plantar flex foot, flex ankle joint
Plantaris Tibial Insignificant plantar flexor
Deep group Unlocks knee in flexion and also
Popliteus Tibial Laterally rotates femur Tibialis posterior Tibial Plantar flex, inverts foot Flexor hallucis longus Tibial Flex big toe, plantar flex foot Flexor digitorum longus Tibial Flex toes, plantar flex foot
Popliteal fossa
Superiorly and medially: semimebranosus, semitendinosus Superiorly and laterally: biceps femoris
Inferiorly and medially: medial head of gastrocnemius Inferiorly and laterally: lateral head of gastrocnemius Floor [anteriorly]: popliteal surface of distal femur Roof [posteriorly]: deep popliteal fossa
Contents: [superficial to deep] tibial N., popliteal V, popliteal A., popliteal LN, small saphenous V., common peroneal and tibial N., posterior cutaneous N. of the thigh Nerves found: sciatic [tibial+peroneal N] and posterior femoral cutaneous N. Nerves of the leg [refer to Netter p. 483-484]
Name Origin Features
Tibial N. Formed by L4-5,
S1-3 Supplies all muscles of posterior leg compartmentBranches: medial sural cutanous, medial calcaneal Common peroneal Sciatic Branches: lateral sural cutaneous N., sural
communicating N., recurrent articular branch Deep peroneal Common peroneal Supplies all muscles of anterior leg compartment Superficial peroneal Common peroneal Supplies on lateral leg and foot
Arteries of leg and popliteal region [refer to Netter p. 483]
Name Branches
Popliteal A. Medial and lateral superior genicular A., medial and lateral inferior
genicuar A., middle genicular A., sural arteries [largest branch]
Genicular anastomosis Receives: popliteal A, femoral A, profunda femoris A. ant. + post. tibial A.
Posterior tibial A. Nutrient A. to tibia, circumflex fibular A, medial posterior malleolar branch
and medial calcaneal branches, peroneal A.
Peroneal A. Muscular branches, nutrient A. to fibula, communicating banch to
posterior tibial A., perforating branch, lateral posterior malleolar A.
Anterior tibial A. Muscular branches, posterior and anterior tibial recurrent, A, medial and
lateral anterior malleolar branches, dorsalis pedis FOOT
Bones of foot 1. tarsal bones [7]
begin ossification before birth except for cuneiform and navicular, w/c begin at 3-4 years of age Components: talus, calcaneus [largest tarsal bone, forms the heel of the foot, ossification at 6
mos.], navicular, cuboid, medial cuneiform [largest of the cuneiform bones], intermediate cuneiform, lateral cuneiform
2. metatarsal bones [5]
begin ossification at shaft in 2 nd -3 rd mos. in utero 2nd metatarsal [longest metatarsal] 5th metatarsal has prominent tubercle on its base 3. phalanges [14]
2 for the great toe and 3 for the remaining toes Begin ossification at the shaft in 3 rd month in utero Composition of foot
Hindfoot Talus, calcaneus Midfoot Navicular, cuboid, cuneiform Forefoot Metatarsals and phalanges
Intrinsic muscles on plantar surface [sole] of foot [refer to Netter p. 497-500]
Name Innervation Actions
1st layer
Abductor hallucis Medial plantar N Abducts great toe Flexor digitorum brevis Medial plantar N Flex lateral 4 toes Abductor digiti minimi Lateral plantar N Abducts little toe 2nd layer
Quadratus plantae Lateral plantar Flex toes when foot is plantar flexed Flexor digitorum
accesorius Lateral plantar Flex lateral 4 toes
Flexor digiorum longus Tibial N. Flex distal phalanges, plantar flex foot Flexor hallucis longus Tibial N. Flex distal phalanx of big toe, plantar flex foot Lumbricals [4] 1st: medial plantar
2-4: lat. plantar Flexes metatarsophalangeal and extend interphalangeal joints 3rd layer
Flexor hallucis brevis Medial plantar Flexes matatarsophalangeal joint of great toe Adductor hallucis Lateral plantar Adducts great toe
Flexor digiti minimi Lateral plantar Flexes metatarsophalangeal joint of little toe 4th layer
Plantar interossei [3] Lateral plantar Adduct toes, flexes metatarsophalangeal jts Dorsal interossei [4] Lateral plantar Abduct toes, flexes metatarsophalangeal jts
Intrinsic muscles on dorsum of foot
Name Innervation Actions
Extensor digitorum brevis Deep peroneal N. Extends toes Extensor hallucis brevis Deep peroneal N. Extends great toe Posterior tibial pulse
Palpated btw posterior surface of medial malleolus & medial border of calcaneal tendon Essential in occlusive peripheral arterial disease
Intermittent claudication characterized by leg cramps during walking and disappears after rest [due to ischemia]
Arteries of foot [refer to Netter p. 495]
Name Branches
Medial plantar A Plantar digital A. to medial side of great toe, anastomotic branches
Lateral plantar A Plantar metatarsal A, , anastomosis w/ deep plantar A.
Dorsalis pedis A Medial and lateral tarsal A, 1st dorsal metatarsal A, arcuate A, deep plantar A
Nerves of foot
Name Origin Distribution
Deep peroneal N Common peroneal Extensor digitorm brevis, extensor hallucis brevis Medial plantar N Tibial N [terminal] Abductor hallucis, flexor hallucis brevis, flexor
digitorum brevis, 1st lumbrical muscles Lateral plantar N Tibial N [terminal] Flexor digiti minimi brevis, plantar and dorsal
interossei, lateral 3 lumbricals, adductor hallucis Saphenous N Femoral Largest branch of femoral nerve, to foot [medial] Fibular nerves Common fibular Dorsum of foot, skin on sides of 1st and 2nd toes Sural nerve Tibial+peroneal Accompanies small saphenous vein Lymphatic drainage of foot
Name Distribution
Medial superficial lymph vessels Drains dorsum of foot and sole Lateral superficial lymph vessels Drains lateral side of foot and sole
Deep lymph vessels Follow the main blood vessels, goes to popliteal LN Nerve injuries of lower extremities [refer to Netter p. 502-506]
Injury Affected Causes Manifestations
Femoral nerve Quadriceps
femoris M. Cathetherization of femoral artery Loss sensation over anterior thigh, medial leg and foot Obturator
nerve Obstetric procedures and pelvic diseases Decreased sensation over upper medial thigh
Sciatic nerve Misplaced
intramuscular injection Footdrop and lost of sensationover the leg Common
peroneal N. Extensors of foot and toes Direct trauma to head of fibula, compression by leg cast
Footdrop
Tibial nerve Puncture wound in
popliteal fossa [-] standing on tiptoes Other Injuries of lower extremities
Ischial bursitis Weaver’s buttom
Trochanteric bursitis Pain to iliotibial tract
Gluteus medius limp Gluteal gait
Piriformis syndrome Compression of sural N. by piriformis Anterior tibilais strain/shin splints Edema and pain on distal 2/3 of tibia Deep fibular nerve entrapment/ski-boot synd. Compression by boots
Gastrocnemius strain/tennis leg Tearing of medial belly of gastrocnemius
Calcaneal bursitis Retroachilles bursitis
Calcaneal spur Heel-spur syndrome
Medial plantar nerve compression Jogger’s foot
Polagra Sever pain on metatarsal joint
Clubfoot/talipes Foot twisted out of position
Pes planus Fallen arches
Claw toes Flexion of metatarsophalangeal joints and
distal interphalangeal joint
Hammertoe Permanent flexion of proximal phalanx at
metatarsophalangeal joint
Hallux valgus Lateral dislocation of great toe
Tarsal tunnel syndrome Tibial nerve entrapment Patellofemoral syndrome/runner’s knee Direct blow to patella Prepatellar bursitis/housemaids knee Friction between skin and patella Subcutaneous infrapatellar bursitis or
clergyman’s knee Friction between skin and tibial tuberosity Deep infrapatellar bursitis Friction between patellar ligament and tibia
Popliteal cyst/baker’s cyst Fluid-filled herniations of synovial membrane of knee joint
Genu varum Tibia diverted medially
Genu vaLgum Tibia diverted Laterally
ACL injury – “anterior drawer sign” Pushed tibialis posterior
PCL injury – “posterior drawer sign” Lands on tibial tuberosity w/ flexed knee RAPID REVIEW
Largest synovial joint of the body: knee joint
Tailor’s muscle and also the longest muscle of the body: sartorius Most superficial muscle in the POSTERIOR leg compartment: gastrocnemius Deepest muscle in POSTERIOR leg compartment: tibialis posterior Strongest dorsiflexor and invertor of foot: tibialis anterior
Most lateral of the ANTERIOR leg compartment muscles: extensor digitorum longus Most important stabilizer at knee joint: quadriceps femoris
Powerful push-off muscle during walking, running and jumping: flexor hallucis longus m.
Largest nutrient artery: Nutrient artery to tibia
Major blood supply to toes: dorsalis pedis A. or dorsal artery of foot Do not act on knee joint: soleus M.
Triceps surae muscle: gastrocnemius [medial and lateral heads] and soleus muscles Hamstring muscles: biceps femoris, semitendinosus & semimembranosus Quadriceps femoris muscles: rectus femoris, vastus medialis, lateralis and
intermedius
Most superficial of the 3 components of popliteal fossa: tibial N.
Only branch of lumbosacral plexus that contains both anterior [S2-3] and posterior [S1-2] division fibers: posterior femoral cutaneous nerve
Largest and longest branch of femoral nerve: saphenous nerve [the only branch of lumbar plexus to cross the knee joint]
Main stabilizer of femur: POSTERIOR cruciate ligament
Buttock quadrant safest for needle: Sciatic nerve [upper outer quadrant of buttock] Inversion vs. Invertion [2ND letter rule]
Inversion of foot Eversion of foot
tIbialis anterior and posterior pErineus longus, brevis, terius CHAPTER 4 – THORAX
THORACIC WALL AND SKELETON [refer to Netter p. 470] Ribs
True ribs [1st 7 ribs] False ribs [8-12 ribs]
12 pairs, attached posteriorly to thoracic vertebrae Typical ribs [3-9] – w/ neck, head, tubercle and body Atypical [1st, 2nd, 10th, 11th, 12th ribs]
Sternum Manubrium Body Xiphoid
Sternal angle of Lewis
Until puberty, consists of 6 sternebrae Widest and thickest of the 3 parts Articulates w/ manubriosternal joint
Increases w/ age and may eventually fuse w/ the body Aka as manubriosternal jt, marks the level of 2nd costal cartilage
Clinical notes Rib fracture
Fractures of a rib commonly occur just ANTERIOR to the angle of the rib [weakest point] and may cause pneumothorax.
Sternal angle of LOUIS – indicates the boundary of: 1. between superior and inferior mediastinum 2. beginning and ending of aortic arch 3. tracheal bifurcation
4. lower border of 4th thoracic vertebrae 5. convenient starting place for counting the ribs 6. the azygos vein drains into the superior vena cava Muscles of the thoracic wall
Name Innervation Actions
Diaphragm Phrenic nerve Main muscle of inspiration, elevates the ribs External intercostals Intercostals N. Assists in inspire/expiration [down & forward] Internal intecostals Intercostals N. Assists in inspire/expiration [down & backward] Innermost intercostals Intercostals N. Assists in inspiration & expiration [transversely] Subcostals Intercostals N. Assists in inspiration and expiration Transversus thoracis Intercostals N. Assists in inspiration and expiration Levator costarum C8-T1 spinal N Elevates rib
Serratus posterior sup. Intercostals N. Assists inspiration by elevating ribs Serratus posterior inf. Intercostals N. Assists expiration by depressing ribs Clinical notes
Phrenic N. lesions
