LOWER
LIMB
ANATOMY
CLASS NOTES
SPRING 2009
KATHY J. SIESEL, D.P.M.
COURSE COORDINATOR
This book of notes is to be used in conjunction with the drawings presented in class. An anatomy atlas will be very useful in this course as will attendance in the lecture and laboratory sessions, and completion of dissections in the laboratory.
TOPIC #1 INTRODUCTION AND REVIEW
I. LOWER EXTREMITY REGIONS AND SURFACES A. Regions
1. Gluteal Region
- the buttock, extends from the posterior iliac crest to the gluteal fold 2. Hip Region / Coxal Region
- anterolateral from inguinal ligament to the inferior extent of the hip joint
3. Thigh Region / Femoral Region
- from the inferior aspect of the pelvis to the knee - has anterior, posterior and medial regions 4. Knee Region / Genus Region
- between thigh and leg regions - has anterior and posterior regions 5. Leg Region / Crus Region
- from the knee to the ankle
- has anterior, posterior and lateral regions a. Calf Region / Sural Region
- the rounded (shapely) part at the proximal posterior leg region 6. Ankle Region / Talus Region
- between the leg and the foot
- includes the medial and lateral malleoli 7. Foot Region / Pes Region
a. Dorsal Region
- the superior part or dorsum of the foot b. Plantar Region
- the inferior part or planta of the foot
- is divided into medial, lateral and central regions c. Calcaneal Region
B. Surfaces of the Lower Limb
- described relative to anatomic position 1. Anterior Surface / Ventral Surface
- the front side of a part, except the foot 2. Posterior Surface / Dorsal Surface
- the back side of a part, except the foot 3. Medial Surface
- the inner side of a part, toward body’s midline 4. Lateral Surface
- the outer side of a part, opposite body’s midline 5. Flexor Surface
- the surface over the flexor muscles
- ex. the flexor surface of the leg is the posterior surface of the leg (opposite for the upper limb, due to limb rotations)
6. Extensor Surface
- the surface over the extensor muscles
- ex. the extensor surface of the thigh is the anterior surface of the thigh (opposite for the upper limb, due to limb rotations) 7. Adductor Surface
- the surface over the adductor muscles
- ex. the adductor surface of the thigh is the medial surface of the thigh 8. Abductor Surface
- the surface generally over the abductor muscles
- ex. the abductor surface of the thigh is the lateral surface of the thigh 9. Patellar Surface
- the anterior surface of the knee region, over the patella 10. Popliteal Surface
- the posterior surface of the knee region 11. Medial Malleolar Surface
- the surface over the medial malleolus of the tibia at the ankle region 12. Lateral Malleolar Surface
- the surface over the lateral malleolus of the fibula at the ankle region 13. Dorsal Surface of the Foot
- the superior surface or dorsum of the foot 14. Plantar Surface of the Foot
II. ANATOMIC POSITION
- The anatomic position is one in which the body is standing erect with the toes and palms facing anterior.
- the position of reference for much terminology
- In relaxed standing, the torso is slightly slouched; the toes are often directed slightly lateral and the palms are facing medially.
III. TERMINOLOGY A. Descriptive
- used to describe position 1. Superior, Cephalic, Cranial
- toward the head
- The knee is superior to the ankle. 2. Inferior, Caudal
- away from the head
- The foot is inferior to the ankle. 3. Anterior, Ventral
- toward the front side
- ventral is usually reserved for embryology
- The patellar surface is anterior to the popliteal surface. 4. Posterior, Dorsal
- toward the back side
- dorsal is usually reserved for embryology, except when referring to the foot’s dorsum
- The popliteal region is posterior to the patellar region. 5. Medial
- closer to the midline (central line) of the body - The hallux (great toe) is medial to the 5th pedal digit. 6. Lateral
- farther from the midline
- The 4th pedal digit is lateral to the hallux. 7. Intermediate
- between 2 structures
- The ankle is intermediate to the leg and foot. 8. Ipsilateral
- on the same side of the body
- The right forearm is ipsilateral to the right lower limb. - most often used for neurology
terminology, descriptive, con’t 9. Contralateral
- on the opposite side of the body
- The left arm is contralateral to the right thigh. - most often used for neurology
10. Proximal
- closer to the origin/main structure - The thigh is proximal to the leg. 11. Distal
- farther from the origin/main structure - The foot is distal to the knee.
12. Superficial
- closer to the surface - Skin is superficial to bone. 13. Deep
- farther from the surface, closer to the center - Muscles are deep to skin.
B. Terminology of Movement 1. Flexion
- decreasing the angle between body parts, generally
- usually an anterior direction except at the knee and more distal joints where it is a posterior direction
2. Extension
- increasing the angle between body parts, generally
- usually a posterior direction except at the knee and more distal joints where it is an anterior direction
a. Hyperextension
- extension beyond the anatomic position
- occurs normally at the neck, wrist, hip, ankle and MTP joints; The term is not usually used for hip, ankle or MTP joints
3. Abduction
- moving a part away from the body’s midline 4. Adduction
- moving a part toward the midline of the body 5. Rotation
- moving around the long axis of a part
terminology of movement, rotation, con’t
a. Medial Rotation / Internal Rotation
- anterior surface of the part moves toward the body's midline b. Lateral Rotation / External Rotation
- anterior surface of the part moves away from the body's midline 6. Circumduction
- movement of a part in a circular pattern
- combines flexion and extension with abduction and adduction; movements must occur in alternating sequence
7. Eversion
- moving the sole of the foot away from the body’s midline 8. Inversion
- moving the sole of the foot toward the body’s midline 9. Dorsiflexion
- extension of the ankle joint or joints distal to the ankle joint
- bringing the dorsum of the foot closer to the anterior surface of the leg 10. Plantar Flexion
- flexion of the ankle joint or joints distal to the ankle joint
- moving the dorsum of the foot farther from the anterior surface of the leg 11. Supination
- We will discuss supination as it relates to lower extremity anatomy, not the upper limb.
- combination of plantar flexion, adduction and inversion of the foot - motion occurs at the functional subtalar joint and the midtarsal joint 12. Pronation
- We will discuss pronation as it relates to lower extremity anatomy, not the upper limb.
- combination of dorsiflexion, abduction and eversion of the foot - motion occurs at the functional subtalar joint and the midtarsal joint IV. BODY PLANES
A. Frontal Planes / Coronal Planes
- divide the body or body parts into anterior and posterior sections B. Transverse Planes
- divide the body or body parts into superior and inferior sections C. Sagittal Planes
body planes, sagittal planes, con’t
1. Midsagittal Plane / Median Sagittal Plane - divides into equal right and left halves 2. Parasagittal Plane
- any sagittal plane except the midsagittal plane D. Cardinal Body Planes
- that plane which divides the body into equal parts 1. Cardinal Sagittal Plane
- the midsagittal plane
2. Cardinal Frontal Plane / Cardinal Coronal Plane
- divides the body into equal anterior and posterior halves 3. Cardinal Transverse Plane
- divides the body into equal superior and inferior halves V. JOINTS / ARTICULATIONS
- where two bones meet A. Arthrology
- the study of joints B. Classification
1. Functional
- based on the amount of movement available at a joint a. Synarthrosis - an immovable joint
ex. sutures of the skull
b. Amphiarthrosis - a slightly movable joint ex. symphysis pubis
c. Diarthrosis - a freely movable joint - primarily these in lower limb ex. hip joint
2. Structural
- based on the material that unites the bone ends a. Fibrous - united by fibrous tissue
i. Sutures - of the skull
- functional synarthroses
ii. Gomphosis - between a tooth and the alveolus/socket - functional synarthroses
joints, structural classification, fibrous, con’t
iii. Syndesmosis – 2 bones held together by a sheet of fibrous tissue ex. tibiofibular syndesmosis
- functional amphiarthroses b. Cartilaginous - united by cartilage
i. Primary Cartilaginous Joints – united by hyaline cartilage - temporary joints
ex. Epiphyseal/growth plates - functional synarthroses ii. Secondary Cartilaginous Joints
- united by fibrocartilage - permanent joints
ex. intervertebral discs or symphysis pubis - functional amphiarthroses
c. Synovial – primary type in lower limb - 5 components of synovial joints
articular capsule/fibrous joint capsule unites the bone ends articular cartilage (usually hyaline cartilage) on the bone ends
synovial membrane lines the joint cavity except the articular cartilage and produces synovial fluid
synovial fluid produced by the synovial membrane and fills the joint cavity
- lubricates and protects the articular cartilage
joint cavity, space between the bone ends and within the capsule - all synovial joints are functional diarthroses
i. Plane/Planar/Gliding
- bone ends are both flat surfaces
- allow gliding movements only, no rotation ex. intertarsal joints
ii. Hinge/Ginglymus
- complex surface shapes that may involve more than 2 bones - allow movement in one plane; flexion and extension
ex. ankle joint
iii. Condyloid/Ellipsoid
- 1 rounded, ball-like projection and 1 shallow saucer-like surface - allow movement in two planes; flexion and extension, abduction and adduction, and circumduction
ex. metatarsophalangeal joints iv. Saddle/Sellar
- 2 saddle shaped surfaces
- allow movement in two planes; flexion and extension or abduction and adduction (not both at the same time)
- have a small amount of rotation due to joint surface shapes ex. calcaneocuboid joint
joints, synovial, con’t
v. Bicondylar
- 2 large rounded projections contacting 2 saucer-like areas - allow movement primarily in one plane with a small amount of rotation
ex. knee joint
vi. Ball and Socket/Spheroid
- 1 large rounded, ball-like projection and 1 cup-like depression - allow movements in three planes
- have all movements - flexion, extension, abduction, adduction, circumduction, internal rotation and external rotation
ex. hip joint
VI. BONE A. Osteology
- the study of bone 1. Ligament
- dense connective tissue that connects bone to bone - often blend with articular capsules
B. Types
1. Compact, cortical or dense - very solid
- appears white on radiographs due to closely packed cells - provides strength to the bone
2. Cancellous, trabecular or spongy
- appears as thin interlaced plates on radiographs due to loosely packed cells
- has good blood supply for rapid healing a. Trabeculae - the "plates" or lattice pieces C. Classification
1. Placement
a. Axial Bones
- part of the axial skeleton
- includes the skull, vertebrae, ribs, sternum and manubrium b. Appendicular Bones
bone, appendicular, con’t
i. Upper Limb - pectoral girdle (scapula and clavicle), humerus, radius, ulna, carpus, metacarpus, and manual phalanges
ii. Lower Limb - pelvic girdle (os coxa), femur, patella, tibia, fibula, tarsus (greater and lesser), metatarsus, and pedal phalanges (in the toes)
2. Shape
a. Long Bones
- usually have greater length than width - found in the limbs
- slight posterior/plantar concavity (curvature) in the lower limb for strength ex. femur
i. Diaphysis/Shaft/Body - the central tubular part - primarily compact bone
aa. Medullary Cavity
- the hollow core in the diaphysis - contains bone marrow
ii. Epiphyses - the ends of the bone
- core of cancellous bone with a thin covering of compact bone, areas of articulation are covered with cartilage
- epiphysis is singular
iii. Metaphyses - flared part between the diaphysis and the epiphyses - core of cancellous bone with a thin covering of compact bone - metaphysis is singular
b. Short Bones
- roughly cube-shaped
- found only in the carpus and tarsus
- core of cancellous bone with a thin covering of compact bone ex. cuboid and cuneiforms
c. Irregular Bones
- complex shapes with varying amounts of cancellous and compact bone ex. vertebrae and facial bones
d. Flat Bones
- two parallel plates of compact bone with a minute amount of cancellous bone between the two plates
bone, shapes, con’t
e. Sesamoid Bones
- round or oval bones located within tendons and often joint capsules - functions:
1. protect the tendon from wear
2. create a mechanical advantage for the muscle by changing the angle of the pull and altering the muscle action
ex. patella - largest sesamoid in the body
and the sesamoids of the first metatarsal bone f. Accessory Bones / Accessory Ossicles
- small bones with smooth regular edges
- may be a non-fused portion of an existing bone or an extra bone - may be located within joint capsules
ex. os intermetatarseum (between the metatarsal bases) and os supratalare
- many in the foot D. Bone Markings
The parentheses contain plural forms of these terms, which are not typical English plurals.
1. Foramen (foramina)
- an opening (hole) for the passage of vessels and nerves ex. nutrient foramen, sacral foramina
2. Sulcus, Groove (sulci)
- a ditch-like furrow for the passage of soft tissue structures ex. obturator groove, lateral malleolar sulcus
3. Fossa (fossae)
- a depression in or on a bone
ex. iliac fossa, lateral malleolar fossa 4. Notch
- an indentation along the edge of a bone ex. greater sciatic notch
5. Condyle
- a large rounded or depressed articular prominence ex. medial femoral condyle
6. Epicondyle
- a small prominence superior to a condyle ex. medial epicondyle of the femur 7. Facet
- a smooth flat surface for articulation ex. middle facet of the calcaneus
bone, bone markings, con’t 8. Tubercle
- a small rounded prominence for the attachment of soft tissue structures ex. adductor tubercle of the femur
9. Tuberosity
- a large rounded prominence, often roughened for the attachment of soft tissue structures
ex. tibial tuberosity 10. Trochanter
- a large blunt process only on the femur ex. greater trochanter
11. Crest
- a prominent border or ridge ex. median sacral crest 12. Line, Ridge
- a ridge, much less prominent than a crest ex. soleal line of the tibia
E. Ossification
- all lower extremity bones begin as cartilage except the tufts of the distal phalanges
- the tufts of the distal phalanges ossify through a process called intramembranous ossification
- the ossification process from cartilage to bone is called
endochondral bone formation or intracartilaginous ossification 1. Long Bones
a. Primary Ossification Center - at midshaft of the bone
- Primary ossification centers of all of the lower limb long bones are present at birth.
- forms the major part of the diaphysis b. Secondary Ossification Centers - in the extremities (ends)
- may be present at birth
- one or more for each extremity - form the epiphyses
c. Epiphyseal Plate/Physis
- area of cartilage between the diaphysis and the epiphyses - allows for length-wise growth of bone
bone, ossification, con’t 2. Short Bones
a. Center of Ossification - in the bone’s center
- The center of ossification of some short bones is present at birth. - most only have one center of ossification
- the calcaneus is an exception
- secondary center of ossification is located posteriorly and is called the calcaneal apophysis
b. Determination of Age
- The appearance of the centers of ossification of the short bones of the foot can be used to determine a child's age radiographically. Using the bones of the hand is more accurate as there is less variability in the age of appearance of the centers of ossification of the manual short bones.
VII. MUSCLES
A. Myology - the study of muscles 1. Associated Structures
a. Tendon - connective tissue continuation of the muscle - attaches muscle to bone
i. Tendon Sheath - a double layer of connective tissue around a tendon with a small amount of fluid between the layers - allows tendon to glide freely when the muscle contracts or relaxes and prevents friction or damage to the tendon
aa. Mesotendon - where the layers of tendon sheath meet each other - may remain as a single structure or partially or
completely degenerate
- Vincula - name given to areas of mesotendon that are present on the flexor tendons of the hand or foot - function: are areas for passage of vessels that
nourish the tendon
ii. Watershed Area - on tendons that do not have tendon sheaths - the area of a tendon where there is the greatest potential of
injury due to a lack of blood supply
- tendons without sheaths receive blood from the bone to which it attaches and from the muscle, majority from muscle
- this creates an area where the two sources meet at the watershed b. Aponeurosis - flat connective tissue sheet
- attaches muscle to muscle, muscle to bone or muscle to skin ex. plantar aponeurosis/plantar fascia
muscles, associated structures, con’t
c. Bursa - a fluid-filled sac that decreases friction between 2
structures; ligament and bone, ligament and ligament, muscle and bone, tendon and tendon, bone and skin
i. Adventitious Bursa - located just beneath the skin and develops as a result of abnormal friction
ex. over a bunion
B. Types
1. Cardiac Muscle
- heart muscle tissue
2. Non-striated Muscle / Smooth Muscle - muscle of viscera
3. Skeletal
- voluntary muscle
- also called striated muscle
- poor terminology because cardiac muscle is also striated - preferable not to use this term
a. Belly - contractile part of a skeletal muscle - actual muscle tissue
b. Origin - the functional stable attachment that does not move
- the proximal attachment from an anatomic view (and in this course) c. Insertion - the functional mobile attachment
- the distal attachment from an anatomic view (and in this course)
C. Naming
1. Direction of fibers
- with respect to the body midline/part midline a. Rectus - parallel to midline
ex. rectus femoris muscle and rectus abdominis muscles b. Transversus - perpendicular to midline
ex. transversus abdominis muscle and transverse head of adductor hallucis muscle
c. Oblique - angle less than perpendicular to the midline ex. oblique head of adductor hallucis muscle and
muscles, naming, con’t 2. Location
- within the body
ex. tibialis anterior muscle and plantar interossei muscles 3. Size
a. Maximus - largest
ex. gluteus maximus muscle b. Minimus - smallest
ex. gluteus minimus muscle c. Magnus - large
ex. adductor magnus muscle d. Longus - longest
ex. adductor longus muscle e. Brevis - shortest
ex. adductor brevis muscle 4. Number of Origins
a. quadriceps femoris muscle has 4 origins b. biceps brachii muscle has 2 origins 5. Shape
a. quadratus plantae muscle – quadrangular b. trapezius muscle - trapezoid
6. Origin and/or Insertion a. sternocleidomastoid muscle
- mastoid process, sternum and clavicle b. iliacus muscle
- iliac fossa 7. Action/Function
a. flexor digitorum longus muscle - flexes the digits
b. abductor hallucis muscle - abducts the hallux
D. General Rule: Any muscle that crosses a joint has an action at that joint. (If you know the origin, course and insertion of a muscle, you can figure out the action or function.)
VIII. VESSELS A. Types 1. Arteries
- carry blood away from the heart a. Conducting / Elastic
- large arteries
- lumen diameter greater than wall thickness
-ex. aorta, branches from aortic arch and the common iliac arteries - conduct blood (from the heart) to medium-sized arteries
i. Vasa Vasorum - tiny vessels within the walls of conducting arteries to nourish these large vessels
b. Distributing / Muscular - medium-sized arteries
- lumen diameter about equal to wall thickness
-ex. external and internal iliac, femoral, popliteal, anterior and posterior tibial, and peroneal arteries
- distribute blood to different body parts; to arterioles in these parts c. Arterioles
- small to very small arteries
- large amount of smooth muscle in the walls that can change blood pressure by contracting or relaxing
- supply individual structures within parts
- direct blood to capillary beds; for exchange of nutrients and wastes d. End
- an artery that is the only blood supply for an area - occlusion results in death of area
-ex. ophthalmic artery, proper digital arteries 2. Veins
- carry blood toward the heart
- distal to proximal direction in limbs - valves - present within the veins - prevent the back flow of blood
- aid the muscular pump in lower limbs to return blood to the heart; muscles contract and compress veins, blood flows proximal a. Veins / Venae Comitans
- large veins
- a vena comitans travels with its respective artery ex. femoral artery and femoral vein
i. Vasa Vasorum - tiny vessels within the large vessel walls to provide nourishment
vessels, veins, con’t
b. Venae Comitantes / Venules
- 2 or 3 small veins that accompany an artery - inferior to the knee in lower limb
- referred to as venae comitantes of the _______ artery (ex. anterior tibial)
- small veins that carry blood to large veins 3. Capillaries
- microscopic vessels that allow exchange of nutrients and wastes for cells - direct blood to venules
4. Lymph Vessels
- vessels that carry lymph fluid (like plasma), which extravasates (escapes) from capillaries
- valves - present within lymph vessels
- greater number than in veins; due to lower pressure in the lymphatic system to prevent back flow of the lymph fluid
a. Lymph Capillaries - microscopic vessels that begin between cells; open-ended
- transport lymph to afferent lymph vessels
b. Afferent Lymph Vessels - small vessels that carry lymph fluid to lymph nodes
c. Lymph Nodes - oval or kidney-shaped structures that filter lymph fluid before returning it to the general circulation
d. Efferent Lymph Vessels - small vessels that carry lymph fluid away from from lymph nodes
e. Lymph Trunks - large lymph vessels that collect lymph fluid from a region
-ex. lumbar trunk collects from lower limb
B. Anastomoses
- communications between arteries and/or veins 1. Arterial
- artery to artery communication
- provides alternate source of blood supply to an area; more than one route to the same end
- often called "collateral circulation", however it is actually not because collateral circulation has new vessels
vessels, anastomoses, con’t
2. Venous - vein to vein communication - provides alternate return route for blood
- very common; possibly because of the lower pressure in the venous system as compared to the arterial system which makes it easier to occlude venous vessels
C. Arteriovenous Shunts
- communication between an arteriole and a venule
- help regulate body temperature by directing blood away from the surface to deeper tissues or to the surface from deeper tissues
- can be traumatically induced as in gunshot wounds and may need to be surgically repaired
D. General Rule: Arteries tend to cross the flexor surface of muscles to prevent collapse, so they do not get stretched to closing or crushed.
IX. NERVES
A. Central Nervous System (CNS)
- contained within the skull and spinal column 1. Brain
- within the skull
a. Afferent Fibers - carry impulses to nerve cell bodies in the brain
b. Efferent Fibers - carry impulses to other (lower) nerve cell bodies in the CNS c. Nerve Cell Bodies
2. Spinal Cord
- within the spinal column
a. Afferent Fibers - carry impulses to other (higher) neurons in the CNS b. Efferent Fibers - carry impulses to other (lower) neurons in the CNS
c. Nerve Cell Bodies - in the central grey matter - dorsal, ventral and lateral horns
3. Spinal Roots
- within the spinal column
- inferior to the spinal cord near the second lumbar vertebra, the spinal roots are long and are called Cauda Equina which means horse's tail
nerves, spinal roots, con’t
a. Dorsal Root/Dorsal Spinal Root
i. Afferent Fibers - carry sensory impulses from peripheral areas to nerve cell bodies in the dorsal root ganglion
ii. Dorsal Root Ganglion - collection of nerve cell bodies in the dorsal root b. Ventral Root/Ventral Spinal Root
i. Efferent Fibers - carry motor impulses from nerve cell bodies in the central nervous system to peripheral areas (muscles)
B. Peripheral Nervous System (PNS) - outside the skull and spinal column 1. Spinal Nerves
- junction of dorsal and ventral roots, located at the intervertebral foramina a. Dorsal Primary Rami / Dorsal Primary Ramus
- contain afferent and efferent fibers
- caudal ones are small branches; lumbar, sacral and coccygeal dorsal rami supply motor and sensory innervation to the muscles of the spinal column b. Ventral Primary Rami / Ventral Primary Ramus
- contain afferent and efferent fibers
- large branches; lumbar, sacral and coccygeal ventral rami form plexuses and supply motor and sensory innervation to the lower limb
C. Autonomic Nervous System (ANS)
- innervates the viscera and smooth (non-striated) muscle of blood vessels and glands
- an efferent or motor system 1. Sympathetic Nervous System
- responses of stress or emergency situations - "fight, fright and flight" responses - increased heart rate and blood pressure
- arise from thoracic and lumbar spinal cord and are distributed via the sympathetic chain; lower limb supply from T-10 through L-2 segments - follow blood vessels (external iliac and femoral aa.) or nerves (femoral n.) in the lower limb
nerves, ANS, con’t
2. Parasympathetic Nervous System - conservation responses
- decreased heart rate and respiration
- arise from cranial and sacral segments of the central nervous system
- follow other nerves or form nerves (pelvic splanchnic nerves) to supply the area - no supply to lower limb
Topic # 2
SUBCUTANEOUS LAYER, DEEP FASCIAE AND
RETINACULA, NAIL ANATOMY, DERMATOMES
I. SUPERFICIAL FASCIA
A. Def'n: the subcutaneous layer, immediately deep to the skin/cutaneous layer - composed of loose connective tissue and adipose (fat) tissue
B. Contents
- superficial veins, superficial lymph nodes and lymph vessels, and cutaneous nerves 1. Superficial Veins
- carry blood from inferior to superior - can generally be seen through the skin - in athletes, many bulge beneath the skin
- in general, pass superficial to the cutaneous nerves a. Common Dorsal Digital Veins (8)
- label as 1 to 8 from medial to lateral or as medial and lateral of the digit - collect blood from the toe and drain into dorsal metatarsal veins
ex. the 1st and 2nd common dorsal digital veins drain into the 1st dorsal metatarsal vein; and so on
b. Proper Dorsal Digital Veins (2)
i. Proper Dorsal Digital Vein of the Hallux
- drains from the dorsomedial aspect of the hallux and 1st metatarsophalangeal joint
- becomes the medial marginal vein ii. Proper Dorsal Digital Vein of the 5th Toe
- drains from the dorsolateral aspect of the 5th toe and 5th metatarsophalangeal joint
superficial veins, con’t c. Marginal Veins
- much variation with veins, can be difficult to distinguish these, may be absent i. Medial Marginal Vein
- drains from the medial border of the forefoot and the proper dorsal digital vein of the hallux
- drains into the great saphenous vein
ii. Lateral Marginal Vein
- drains from the lateral border of the forefoot and the proper dorsal digital vein of the 5th toe
- drains into the small saphenous vein d. Dorsal Metatarsal Veins (4)
- one for each intermetatarsal space
- label as 1 through 4 from medial to lateral
- each receives blood from 2 adjacent common dorsal digital veins and two perforating branches from deep layers of the foot
- drain into the dorsal venous arch e. Dorsal Venous Arch
- passes across the dorsum of the foot often at the level of the metatarsal bases - receives blood from dorsal metatarsal veins and sometimes the proper dorsal digital veins
- drains into the great saphenous vein, medially and the small saphenous vein, laterally
f. Small Saphenous Vein
- begins as the union of the lateral end of the dorsal venous arch and the lateral marginal vein (or the proper dorsal digital vein of the fifth digit), then passes posterior to the lateral malleolus at the ankle region
- travels superiorly near the midline of the leg, at the posterior aspect, to the popliteal area where it passes through the deep fascia to join the popliteal vein, which is part of the deep venous system
g. Great Saphenous Vein
- begins as the union of the medial part of the dorsal venous arch and the medial marginal vein (or the proper dorsal digital vein of the hallux), then passes anterior to the medial malleolus at the ankle region
- travels superiorly at the medial aspect of the leg, passes posteromedially along the popliteal surface (usually about 1 hand breadth posterior to the medial edge of the patella) and continues in a superolateral direction to the groin where it passes through the saphenous opening/fossa ovalis in the deep fascia to join the femoral vein which is part of the deep venous system h. Superficial Plantar Venous Network
- very thin intradermal and subdermal veins without valves
- drain into medial and lateral marginal veins or into dorsal digital veins through perforating branches
superficial fascia, contents, con’t 2. Lymph Nodes
a. Inguinal Lymph Nodes
- located in the inguinal region, groin (where the thigh meets the hip) - organized as 3 groups
i. Superficial Inguinal Lymph Nodes
- lie in the superficial fascia and are arranged as 2 groups
- are usually palpable, but are firm and tender (painful to the patient) when inflamed
- most efferent vessels pass to the external iliac lymph nodes in the pelvis; a few pass to the deep inguinal lymph nodes
aa. Horizontal Group
- lie along the inguinal ligament
- drains the superficial areas of the inferior abdominal wall and a small area of the proximal anterior thigh
bb. Vertical Group
- lie along the termination of the great saphenous vein and the fossa ovalis - drains from the superficial areas of the thigh, leg and foot except the posterolateral aspect of the leg and the lateral aspect of the foot ii. Deep Inguinal Lymph Nodes (not pictured)
- palpable only when inflamed
- lie deep to the fascia lata, along the femoral vein near its termination - not in the subcutaneous layer
- drain the deep tissues of the lower limb (tissues deep to the deep fascia) - efferent vessels pass to the external iliac lymph nodes in the pelvis b. Popliteal Lymph Nodes
- are deep lymph nodes and palpable only when inflamed
- lie along the small saphenous vein near its termination and deep to the popliteal fascia
- drain the posterolateral aspect of the leg and the lateral aspect of the foot - efferent vessels pass to the deep inguinal lymph nodes
c. Anterior Tibial Lymph Node (not pictured) - usually one or two deep lymph node(s)
- lie near the proximal end of the anterior tibial artery near the interosseous membrane, deep to the muscles here
- efferent vessels pass to the deep inguinal lymph nodes d. Subcutaneous Pedal Infections
- an infection of the 5th toe will generally cause inflammation of the popliteal lymph nodes first, then inflammation of the deep inguinal lymph nodes - an infection of the hallux will generally cause inflammation of the vertical superficial inguinal lymph nodes first and this may pass to the deep inguinal lymph nodes, but definitely will pass to the external iliac lymph nodes
superficial fascia, contents, con’t
e. Deep Pedal Infections / Deep Infections of the Foot
- from any area, will create inflammation of the deep inguinal lymph nodes - from dorsum of foot, will generally create inflammation of the anterior tibial lymph node, first
- from planta of foot and calcaneal region, will generally create inflammation of the popliteal lymph nodes, first
3. Cutaneous Nerves
- are nerves that exit the deep fascia and travel in the superficial fascia to supply the skin, sensory and autonomic sympathetic fibers
- all are from ventral rami except where noted - know these a. anterior view
i. Subcostal Nerve, T-12
- exits the deep fascia anterior to the iliac tubercle (lateral aspect of the hip) - supplies a small area at the anterolateral aspect of the thigh just inferior to
the groin
- cutaneous supply only in lower extremity
ii. Femoral Branch of the Genitofemoral Nerve, L-1 & L-2
- passes deep to the inguinal ligament and exits the deep fascia near the fossa ovalis
- supplies a small area at the anterior thigh just inferior to the groin and medial to subcostal nerve distribution
iii. Ilioinguinal Nerve, L-1
- exits the deep fascia through the superficial inguinal ring (with the spermatic cord or round ligament of uterus)
- supplies a small area at the medial aspect of the thigh just inferior to the groin
iv. Lateral Femoral Cutaneous Nerve, L-2 & L-3 - also called the lateral cutaneous nerve of the thigh
- exits the deep fascia near the anterior aspect of the iliac crest
- supplies the anterolateral aspect of the thigh (from the subcostal nerve distribution to the knee)
v. Intermediate Femoral Cutaneous Nerve, L-2 & L-3 - also called the intermediate cutaneous nerve of the thigh
- sometimes replaced by the femoral branch of the genitofemoral nerve or branches of the lateral femoral cutaneous nerve
- exits the deep fascia through the sartorius muscle lateral to the fossa ovalis - supplies the anterior aspect of the thigh (from the ilioinguinal and
genitofemoral nerve distributions to the knee) vi. Medial Femoral Cutaneous Nerve, L-2 & L-3 - also called medial cutaneous nerve of the thigh - exits the deep fascia inferolateral to the fossa ovalis
- supplies the anteromedial aspect of the thigh (from the ilioinguinal nerve distribution to the knee)
cutaneous nerves, anterior view, con’t vii. Obturator Nerve, L-2, L-3 & L-4
- exits the deep fascia at the medial aspect of the thigh near the junction of the proximal and middle thirds
- supplies the central part of the medial aspect of the thigh (from the ilioinguinal nerve distribution to the inferior 1/3)
viii. Lateral Cutaneous Nerve of the Calf, L-5, S-1 & S-2 - also called the lateral sural nerve
- exits the deep fascia at the posterolateral edge of the knee region - supplies the lateral 1/2 of the leg from the knee to the inferior 1/3 leg ix. Saphenous Nerve, L-3 & L-4
- the only nerve of the leg region that can be traced to the lumbar plexus - exits the deep fascia at the inferomedial aspect of the thigh near the knee - supplies the entire medial ½ of the leg from the knee to the foot including
the medial longitudinal arch; does not include the heel
x. Superficial Fibular Nerve / Superficial Peroneal Nerve, L-4, L-5 & S-1 - exits the deep fascia at the anterolateral aspect of the leg near midlevel - supplies the anterolateral aspect of the inferior 1/3 of the leg, the
anterolateral aspect of the ankle and the dorsum of the foot except the lateral ½ of the 5th digit and the 1st web space
xi. Deep Fibular Nerve / Deep Peroneal Nerve, L-5, S-1 & S-2 - exits the deep fascia at the 1st webspace
- supplies the 1st web space and the adjacent sides of the 1st and 2nd toes xii. Medial Calcaneal Nerve, S-1 & S-2
- exits the deep fascia at the posteromedial aspect of the ankle near the calcaneus; pierces the flexor retinaculum
- supplies the medial ½ of the heel; medially, plantarly and posteriorly
xiii. Sural Nerve, S-1 & S-2
- exits the deep fascia at the posterior aspect of the leg in the proximal 1/3 - supplies a small area of the posterior aspect of the leg from mid-calf, to
the posterolateral aspect of the ankle, the lateral aspect of the foot, the lateral longitudinal arch and the lateral ½ of 5th toe
b. posterior view
i. Iliohypogastric Nerve, L-1
- exits the deep fascia near the lateral aspect of the iliac crest
- supplies the superoposterolateral area of the gluteal skin, small area ii. Superior Cluneal Nerves, dorsal rami of L-1, L-2 & L-3
- also called the superior cutaneous nerves of the gluteal region - exit the deep fascia at the posterior aspect of the iliac crest - supply skin of superolateral aspect gluteal region
cutaneous nerves, posterior view, con’t
iii. Middle Cluneal Nerves, dorsal rami of S-1, S-2 & S-3
- also called the middle cutaneous nerves of the gluteal region - exit the deep fascia over the sacrum
- supply skin of the medial aspect gluteal region iv. Posterior Femoral Cutaneous Nerve, S-1, S-2 & S-3
- main branch passes inferiorly along the anterior aspect of the fascia lata - small branches from the main branch exit the deep fascia all along the
posterior aspect of the thigh, popliteal and calf regions
- supplies the inferior gluteal region, the posterior aspect of the thigh, the popliteal fossa and the superior central aspect of the calf
aa. inferior cluneal nerves, S-1, S-2 & S-3
- branches of the posterior femoral cutaneous nerve that supply the inferior area of the gluteal region
- exit the deep fascia at the gluteal fold v. Perforating Cutaneous Nerve, S-2 & S-3 - branch from the sacral plexus
- exits deep fascia at the inferomedial aspect of the gluteal region - supplies the inferomedial gluteal area skin
vi. Obturator Nerve, L-2, L-3 & L-4 - described above
vii. Medial Femoral Cutaneous Nerve, L-2 & L-3 - described above
viii. Lateral Femoral Cutaneous Nerve, L-2 & L-3 - described above
ix. Saphenous Nerve, L-3 & L-4 - described above
x. Lateral Cutaneous Nerve of the Calf, L-5, S-1 & S-2 - described above
xi. Sural Nerve, S-1 & S-2 - described above
aa. lateral cacaneal nerves, S-1 & S-2 - branches of the sural nerve
- arises in the superficial fascia between the calf and the ankle - supplies the lateral ½ of heel; laterally, plantarly and posteriorly xii. Superficial Fibular Nerve/Superficial Peroneal Nerve, L-4, L-5, S-1 - described above
cutaneous nerves, posterior view, con’t xiii. Medial Plantar Nerve, L-4 & L-5
- small branches exit the deep fascia along the medial 2/3 of the plantar midfoot and forefoot
- supplies the plantar medial aspect of the foot from just distal to the heel to the medial 3½ toes
xiv. Lateral Plantar Nerve, S-1 & S-2
- small branches exit the deep fascia along the lateral 1/3 of the plantar midfoot and forefoot
- supplies the plantar lateral aspect of the foot from just distal to the heel to the lateral 1½ toes
xv. Medial Calcaneal Nerve, S-1 & S-2 - described above
c. cutaneous nerves of the dorsum of the foot
i. Superficial Fibular Nerve / Superficial Peroneal Nerve, L-4, L-5 &S-1 - courses inferomedially and divides just proximal to the ankle
aa. Medial Dorsal Cutaneous Nerve - the medial division
- passes anterior to the ankle near the center and is palpable here - supplies the medial part of the dorsal midfoot, then divides - aids in supply to 1st webspace
- Proper Dorsal Digital Nerve 1 - the medial branch
- supplies the dorsomedial aspect of the hallux - 1st Common Dorsal Digital Nerve
- the lateral branch, passes in the 2nd intermetatarsal space dorsally and divides to supply the adjacent sides of the 2nd and 3rd toes as Proper Dorsal Digital Nerves 4 and 5, respectively
bb. Intermediate Dorsal Cutaneous Nerve
- the lateral division of the superficial fibular nerve - passes anterior to the ankle near the lateral malleolus - is easily palpated here
- supplies the dorsolateral part of the midfoot and divides - 2nd Common Dorsal Digital Nerve
- the medial branch, passes in the 3rd intermetatarsal space dorsally and divides to supply the adjacent sides of the 3rd and 4th toes as Proper Dorsal Digital Nerves 6 and 7, respectively
- 3rd Common Dorsal Digital Nerve
- the lateral branch, passes in the 4th intermetatarsal space dorsally and divides to supply the adjacent sides of the 4th and 5th toes as Proper Dorsal Digital Nerves 8 and 9, respectively
cutaneous nerves, dorsum of foot, con’t
ii. Lateral Dorsal Cutaneous Nerve, S-1 & S-2 - is already in the superficial fascia at this level
- the continuation of the sural nerve once it passes posterior to the lateral malleolus; the sural nerve is renamed at this point
- supplies the lateral border of the foot aa. Proper Dorsal Digital Nerve 10
- the continuation of the lateral dorsal cutaneous nerve when it enters the fifth toe; the lateral dorsal cutaneous nerve is renamed at this point - supplies the dorsolateral aspect of the 5th toe
iii. Deep Fibular Nerve / Deep Peroneal Nerve, L-5, S-1 & S-2 - exits the deep fascia in the 1st interspace, supplies it and divides aa. Proper Dorsal Digital Nerve 2
- supplies the dorsolateral aspect of the hallux and medial 1st interspace bb. Proper Dorsal Digital Nerve 3
- supplies the dorsomedial aspect of the 2nd toe and lateral 1st interspace iv. Saphenous Nerve, L-3 & L-4
- passes anterior to the ankle near the medial malleolus
- supplies the medial border of the midfoot and part of the medial longitudinal arch
d. cutaneous nerves of the plantar foot i. Medial Plantar Nerve, L-4 & L-5
- passes along the foot deep to the plantar fascia, sends cutaneous branches to the skin and divides near the forefoot
aa. Proper Digital Plantar Nerve 1
- passes along the medial side of the forefoot, plantarly, exiting the deep fascia near the distal 1st metatarsal shaft
- supplies the plantar medial aspect of the hallux and 1st metatarsophalangeal joint
bb. 1st Common Digital Plantar Nerve
- passes in the area of the 1st intermetatarsal space, plantarly - exits the deep fascia at the level of the metatarsal necks
- supplies this area and adjacent sides of the hallux and 2nd toe as the Proper Digital Plantar Nerves 2 and 3, respectively
cc. 2nd Common Digital Plantar Nerve
- passes in the area of the 2nd intermetatarsal space, plantarly - exits the deep fascia at the level of the metatarsal necks
- supplies this area and adjacent sides of the 2nd and 3rd toes as the Proper Digital Plantar Nerves 4 and 5, respectively
cutaneous nerves, planta of foot, con’t
dd. 3rd Common Digital Plantar Nerve
- passes in the area of the 3rd intermetatarsal space, plantarly - exits the deep fascia at the level of the metatarsal necks
- supplies this area and adjacent sides of the 3rd and 4th toes as the Proper Digital Plantar Nerves 6 and 7, respectively
ii. Lateral Plantar Nerve, S-1 & S-2
- passes along the plantar midfoot deep to the deep fascia, sends cutaneous branches to the skin and divides
aa. Communicating Branch
- a medial branch which joins the 3rd common digital plantar nerve bb. 4th Common Digital Plantar Nerve
- passes in the area of the 4th intermetatarsal space, plantarly - exits the deep fascia at the level of the metatarsal necks
- supplies this area and adjacent sides of the 4th and 5th toes as the Proper Digital Plantar Nerves 8 and 9, respectively
cc. Proper Digital Plantar Nerve 10
- passes along the lateral forefoot, plantarly, exiting the deep fascia near the distal 5th metatarsal shaft
- supplies this area of the forefoot and the plantar lateral aspect of the 5th toe
iii. Saphenous Nerve, L-3 & L-4
- supplies a small area of the medial longitudinal arch of the foot, plantarly iv. Sural Nerve, S-1 & S-2
- supplies a small area of the lateral longitudinal arch of the foot, plantarly v. Medial Calcaneal Nerve, S-1 & S-2
- small branches which supply the medial ½ of the calcaneal region vi. Lateral Calcaneal Nerves, S-1 & S-2
- small branches of the sural nerve which supply the lateral 1/3 to 1/2 of the calcaneal region
II. DEEP FASCIAE AND RETINACULA
A. Def'n: deep fascia - dense connective tissue layer that surrounds muscles and attaches to many bony prominences and structures - deep fascia is continuous from one region to the next
retinaculum - thickening of the deep fascia that holds soft tissue structures in place (ex. tendons)
B. Deep Fasciae 1. Fascia Lata
- deep fascia of the thigh
a. Iliotibial (IT) Band / Iliotibial Tract
- thickening of the fascia lata at lateral aspect of the thigh - provides partial origin or insertion site for several muscles
- often visible at lateral edge of extended knee; especially in athletes b. Cribriform Fascia
- very thin area of the fascia lata over the fossa ovalis / saphenous opening near the groin
2. Fascia Cruris
- deep fascia of the leg region
- aids in forming several retinacula near ankle 3. Popliteal Fascia
- deep fascia of the popliteal region 4. Fascia Dorsalis Pedis
- deep fascia of the superior aspect of the foot - aids in forming several retinacula near ankle 5. Plantar Fascia / Plantar Aponeurosis
- deep fascia of the inferior aspect (sole) of the foot, a complex structure - several layers, some fibers attach to skin at all points along the plantar foot - aids in forming the retinacula near the ankle
C. Retinacula
1. Flexor Retinaculum / Laciniate Ligament
- thickening of fascia cruris, fascia dorsalis pedis and plantar fascia
- attaches to the distal posterior aspect of the medial malleolus and to the medial aspect of the calcaneus
- holds flexor tendons of the foot and creates a pulley to improve the muscle function
- all tendons pass through the retinaculum and have separate tendon sheaths here 2. Superior Extensor Retinaculum / Transverse Crural Ligament
- thickening of fascia cruris
- attaches to the distal tibial shaft and to the distal fibular shaft, anteriorly - fibers are continuous with the flexor and superior fibular retinacula
- holds extensor tendons of the foot and maintains their positions near the tibia - only one tendon sheath at this level; for the tibialis anterior muscle
retinacula, con’t
3. Inferior Extensor Retinaculum / Cruciate Crural Ligament - Y-shaped band with the stem laterally
- thickening of fasciae cruris and dorsalis pedis
- attaches to the distal anterior medial malleolus and the medial plantar medial cuneiform, then to the lateral talus (neck) and the superior aspect of the
calcaneus (in the sinus tarsi); described with 3 roots and 7 sinus tarsi attachments - continuous with the inferior fibular retinaculum
- all tendons have tendon sheaths at this level and pass through this retinaculum - frondiform ligament - the stem of the inferior extensor retinaculum, attaches in the sinus tarsi
4. Fibular Retinaculum / Peroneal Retinaculum / External Annular Ligament - really 2 separate retinacula
- thickening of fasciae cruris and dorsalis pedis
a. Superior Fibular Retinaculum / Superior Peroneal Retinaculum
- attaches to the posteroinferior lateral malleolus and to the lateral calcaneus (retrotrochlear eminence)
- formed by fascia cruris
- holds peroneal tendons and creates a pulley at the lateral malleolus - both are in single tendon sheath here and pass deep to retinaculum
- fibers are continuous with superior extensor retinaculum b. Inferior Fibular Retinaculum / Inferior Peroneal Retinaculum
- attaches to the sinus tarsi (anterolaterosuperior calcaneus) and to the
fibular trochlea (posterolaterocentral calcaneus) then to posterolateroinferior calcaneus (near the lateral tubercle)
- formed by fascia dorsalis pedis
- holds peroneal tendons and creates a pulley for fibularis longus tendon at the distoplantar calcaneus
- tendon sheath divides at this point and each tendon passes deep, separately - fibers continuous with lateral root of frondiform ligament
D. Intermuscular Septae (not pictured)
- extensions of deep fascia that attach to bone and separate muscles or groups of muscles
- muscles often take partial origin from or partially insert onto septae - in the leg, these septae aid in venous return (venous pump); there is little elasticity of the septae and muscular action creates compression on the deep veins which forces fluids superiorly (the valves normally prevent inferior flow), the empty deep veins refill from the superficial veins and so on
III. NAIL ANATOMY
A. Parts and Functions 1. Nail Plate
- body of the nail (main part), normally .5 - .75 mm thick in an adult - is a hardening of the epidermis
- cells have no nuclei, therefore are transparent, so can see the capillary bed - function: protect the distal end of the digit / toe
2. Matrix
- "root" of the nail
- specialized cells within the roof and floor of the proximal nail fold - attached to the base of the distal phalanx
- extends approximately 5 mm proximal to visible nail edge - function: produce nail plate
3. Eponychium / Proximal Nail Fold
- the skin fold at the proximal edge of the nail plate - overlies the matrix
4. Cuticle
- small ridge of transparent skin dorsal to the proximal edge of the nail plate which is continuous with the eponychium
- creates a seal around the nail
- function: prevent infection by sealing the area adjacent to the nail plate 5. Nail Bed
- skin directly beneath and attached to the nail plate, contains some nail-
forming cells; the cells that are attached to the nail plate migrate distally and are shed at the free edge of the nail
- from matrix and lunula to the hyponychium
- function: anchor the nail plate and allow its distal growth
- sensory innervation to the nail bed is variable and may be entirely from the proper digital plantar nerves or from the plantar and dorsal proper digital nerves; therefore, you must take care when anesthetizing (blocking) digits for for nail procedures
- it is safest to anesthetize both sets of nerves 6. Lunula
- the small pale half-moon-shaped area near the eponychium; whitish because the cells retain nuclei and the capillaries beneath this portion of the nail plate are not visible
- function: produce nail 7. Free Edge of the Nail Plate
- distal edge of nail plate that overhangs the toe
- function: protect the distal tuft of the toe from blunt trauma (being smashed) 8. Hyponychium
- the thickened skin adjacent to the free edge of the nail plate
nail anatomy, con’t
9. Distal Nail Groove
- the shallow transverse groove between the hyponychium and the skin of the distal tuft of the toe
10. Lateral Nail Folds /Ungualabia
- the convex skin fold at the sides of the nail plate
- after a successful permanent nail procedure the lateral nail folds will abut the remaining nail plate
11. Lateral Nail Grooves
- the concave junction of the lateral nail fold with the nail bed - under the side edges of the nail plate
B. Growth of Nails
- nails grow primarily from the matrix and the proximal nail bed (level of the lunula) and are pushed distally
- the cells of the nail bed migrate with the nail plate
- nails grow faster in younger people and faster in the summer - finger nails grow faster than toe nails
- finger nail takes approximately 6 months for replacement - toe nail takes approximately 9 months for replacement - sickness causes a disturbance in growth of the nail plate
- nail growth requires much protein synthesis and illness retards this - have a resultant transverse ridge / Beau’s Line
- little white spots - due to incomplete keratinization of the nail plate, cells still have nuclei or an air bubble formed in the nail plate due to a minor disturbance in growth
- longitudinal ridges - often due to mechanical damage to the matrix cells
IV. DERMATOMES
A. Def'n: the sensory innervation of an area of skin which is supplied by a single spinal nerve’s dorsal root
B. Distribution in the lower limb
- there is overlap among adjacent segments, so often it is necessary to destroy more than 1 spinal nerve dorsal root to have a noticeable area of deficit - all begin at the spinal level indicated and travel in a general spiral manner as they pass distal
1. L-1 / first lumbar
- posterior at the level of the 1st lumbar vertebra
- supplies an area superior to the hip, posteriorly and superior thigh at the groin near its termination
dermatomes, con’t
2. L-2 / second lumbar
- posterior at the level of the 2nd lumbar vertebra - courses just inferior to L-1
- supplies an area over the posterolateral iliac crest (hip bone prominence) and the anterosuperior aspect of the thigh to the mid-level at the medial aspect of the thigh
3. L-3 / third lumbar
- posterior at the level of the 3rd lumbar vertebra, the mid-low back area - supplies an area over the posterior iliac crest, the superior part of the lateral
aspect of the thigh, the central part of the anterior aspect of the thigh, the inferior part of the medial aspect of the thigh, the medial aspect of the knee region -not the patellar surface- and the superior ½ of the medial aspect of the leg
4. L-4 / fourth lumbar
- posterior at the level of the 4th lumbar vertebra
- supplies an area over the posterosuperior gluteal region, the anteroinferior
thigh, the patellar surface, the central part of the anterior aspect of the leg, the medial malleolus and the medial aspect of the midfoot and forefoot,
including the hallux 5. L-5 / fifth lumbar
- posterior at the level of the 5th lumbar vertebra, the low back - supplies an area over the posterior iliac crest near the spine, the
superolateral gluteal region, the inferior part of the lateral aspect of the thigh, the lateral aspect of the knee region, the anterolateral aspect of the leg, the anterior aspect of the ankle, the central part of the dorsum of the foot, toes 2 through 4, the central part of the plantar aspect of the forefoot and a small part of the calcaneal region (plantar and posterior, lateral to midline)
6. S-1 / first sacral
- posterior at the level of the 1st sacral vertebra, the low back
- supplies an area of the posterior mid-gluteal region, the posterolateral aspects of the thigh and leg, the lateral malleolus, and the lateral aspects of the calcaneal region, midfoot and forefoot, including the fifth toe
7. S-2 / second sacral
- posterior at the level of the 2nd sacral vertebra
- supplies an area of the posterior central gluteal region, the posteromedial
aspects of the thigh (including the perigenital area), knee and leg regions, and the medial ½ of the calcaneal region
8. S-3, S-4, S-5 & Co-1 / third, fourth and fifth sacral and first coccygeal - all begin posteriorly at the respective spinal vertebral level
- all form concentric arcs; with the third sacral being the largest over the posteromedial gluteal area, and the first coccygeal being the smallest around the perianal area
V. MYOTOMES
A. Def'n: the group of muscles that are supplied by a single spinal nerve’s ventral root B. Distribution
- described in terms of movements at joints - have overlap of the segments
- are sometimes reported with slightly different levels because it is difficult to trace nerves
1. Hip Joint
a. Flexion, Adduction, Medial Rotation - L-1 through L-4
b. Extension, Abduction, Lateral Rotation - L-4 through S-1 2. Knee Joint a. Extension - L-2 through L-4 b. Flexion - L-5 & S-1 3. Ankle Joint a. Dorsiflexion - L-4 & L-5 b. Plantar flexion - S-1 & S-2 4. Subtalar Joint a. Inversion/Supination - L-4 & L-5 b. Eversion/Pronation - L-5 & S-1 5. Metatarsophalangeal Joints a. Dorsiflexion - L-5 & S-1 b. Plantar flexion - S-1 & S-2
myotomes, con’t
C. Deep Tendon Reflexes/Spinal Reflexes 1. Def'n:
a. deep tendon reflex (DTR)
- a muscle stretch reflex (These are commonly tested in a physician's office.) - mediated in the spinal cord
b. spinal reflex
- a withdrawal response - a protective reflex
- mediated in the spinal cord 2. Deep Tendon Reflexes
We will discuss the most commonly tested reflexes for the lower limb. There are others, but these test the majority of the spinal segments for the lower limb. a. Patellar Reflex
- at the anterior knee/patellar tendon; with the knee flexed and relaxed, tap the tendon and normally will get a small extension response
- tests spinal segments L-2, L-3 & L-4, the knee extensor myotome b. Achilles Reflex
- at the posterior ankle/Achilles tendon; with the ankle slightly dorsiflexed, tap the tendon and normally will feel the contraction of the calf muscles - tests spinal segments S-1 & S-2; the ankle plantar flexor myotome 3. Spinal Reflexes
a. Babinski Test
- stroke the sole of the foot from central plantar heel in an arc to the base of the fifth metatarsal with a firm blunt object (ex. pen cap, finger nail tip)
- normally will see plantar flexion of the toes; expected reaction
- dorsiflexion of the hallux with abduction of the lesser digits (flaring of toes) is abnormal after 2 years of age
TOPIC #3 OSTEOLOGY - GLUTEAL AND PELVIC REGIONS
I. Pelvis - composed of 4 bones:
2 pelvic (hip) bones, the os coxae 1 sacrum
1 coccyx
- function: contain and protect pelvic organs aid in locomotion via force transfer
osteology of pelvis, con’t
- Pelvic Girdle = 2 pelvic bones
- function: attach lower limb to the trunk A. Sacrum
- forms a primary curvature of spinal column, same direction as fetal curvature - 5 vertebrae fused into one wedge-shaped bone
- recognized by its distinctive shape 1. Base - superior end
- articulates with L-5 vertebra 2. Apex - inferior end
- articulates with the coccyx B. Coccyx (tail bone)
- 4 vertebrae fused into 2 or 3 segments 1. Base - superior end
- articulates with the apex of the sacrum 2. Apex - inferior end
C. Features of Sacrum and Coccyx anterior surface of the sacrum
- concave side to side and superior to inferior 1. Transverse Ridges (4)
- formed by fusion of the vertebral bodies - last area in the body to complete ossification 2. Anterior Sacral Foramina (4 pair)
- allow passage of the ventral rami S-1 through S-4 - holes at anterolateral sacral canal
3. Sacral Promontory
- anterior superior edge of S-1 vertebra - projects in anteroinferior direction in body 4. Sacral Alae (ala means wing)
- expansions from the base, laterally
- the fused transverse processes of S-1 vertebrae 5. Superior Articular Processes
- unfused superior articular processes of S-1
- visible from anterior side, are part of the posterior aspect - articular surface is posterior
anterior surface of coccyx - no true features from anterior
pelvic osteology, sacrum, con’t posterior surface of sacrum 1. Superior Articular Processes
- described above 2. Sacral Alae
- described above 3. Sacral Canal
- spinal canal of the sacrum for passage of cauda equina 4. Median Sacral Crest
- midline projection from sacrum
- the fused spinous processes of S-1 through S-4 5. Sacral Hiatus
- the inferior opening of the sacral canal
- formed by the lamina from S-5 that do not fuse - for passage of meninges and spinal nerves 6. Sacral Cornu
- small projections at the lateral margins of the sacral hiatus - formed by ligamentous attachment
7. Posterior Sacral Foramina (4 pair)
- for passage of dorsal rami S-1 through S-4
8. Intermediate Sacral Crest
- projection at the medial edge of the dorsal sacral foramina, and lateral to the median sacral crest
- formed by fusion of the superior and inferior articular processes 9. Sacral Groove
- depressed area between median and intermediate sacral crests - formed by fusion of the vertebral laminae S-1 through S-4 10. Lateral Sacral Crest
- projection lateral to the dorsal sacral foramina - formed by fusion of the transverse processes posterior surface of coccyx
1. Coccygeal Cornu
- superior articular processes of Co-1 vertebra
pelvic osteology, sacrum, con’t
lateral view of sacrum and coccyx 1. Lateral Surfaces
a. Auricular Surface
- anterior part of the lateral surface, articulates with the pelvic bone - part of the sacroiliac joint, a synovial joint
b. Sacral Tuberosity
- posterior part of the lateral surface, for attachment of ligaments 2. Sacral Ala - described above
3. Sacral Promontory - described above
4. Superior Articular Process - described above 5. Posterior Sacral Foramina 1,4 - described above 6. Median Sacral Crest - described above
7. Sacral Groove - described above
8. Intermediate Sacral Crest - described above 9. Sacral Cornu - described above
10. Lateral Sacral Crest - described above 11. Coccygeal Cornu - described above
D. Ossification of Sacrum
1. Primary Centers of Ossification - all present at birth
- one in each vertebral body, one in each segment of the lateral masses, one in each of the lamina (around the sacral canal)
2. Secondary Centers of Ossification - appear between puberty and age 20 years
- (in the upper and lower surfaces of the bodies, the spinous processes, the transverse processes, and the lateral surfaces)
pelvic osteology, con’t E. Pelvic Bone (2)
- also called os coxa or innominate bone
- articulates posteriorly with the lateral surface of the sacrum, anteriorly with the symphyseal surface of the other pelvic bone and laterally with the femoral head - composed of three bones fused into one
- recognized by its distinctive shape
1. Ilium (not ileum) - the large superior portion of the pelvic bone a. iliac body - the central part (more inferior)
b. iliac ala - the wing (large flattened part)
2. Ischium - the posteroinferior portion of the pelvic bone
a. ischial body - the posterosuperior part; triangular in a cross-sectional view i. femoral surface - the external surface; faces laterally (not seen on picture) ii. pelvic surface - the internal surface; faces medially
iii. dorsal surface - the posterior surface (not seen on picture) b. ischial ramus - the anteroinferior projection
i. anterior surface - the external surface; faces laterally - rough from soft tissue attachment
ii. posterior surface - the internal surface; faces medially - smooth area
3. Pubis - the anteroinferior portion of the pelvic bone a. pubic body - the large anteromedial part
i. symphyseal surface - the flattened medial surface of the body
- articulates with the other symphyseal surface at the pubic symphysis ii. femoral surface - the anterior/external surface (not seen on picture) iii. pelvic surface - the posterior/internal surface (not seen on picture) b. superior pubic ramus - the superior posterolateral projection
i. obturator surface - the anterior surface at the medial end which spirals to an inferior position at the lateral end and is the continuation of the femoral surface of the body
ii. pectineal surface - the superior surface - narrow medially, expands laterally