Organization of the Lower Limb Most illustrations from: Thieme Atlas of Anatomy: Musculoskeletal System. M Schuenke, et al, 2006. Anatomy: A Regional Atlas of the Human Body. Carmine Clemente, 4th edition.

Limb Development Lower limb develops in an anterolateral position at the level of the L2 to S3 trunk segments Great toe positioned in cephalic direction with the soles of the feet in an ateriomedial direction Knee positioned in a posteriolateral position

Limb Rotation Lower Limb Rotation Medial rotation Adduction Extension

Segments of the Lower Limb Limb Girdle pelvic girdle (gluteal) Free limb thigh leg foot

Joints of the Lower Limb

Articulation with Axial Skeleton Sacroiliac jt. Sternoclavicular jt,

Sacroiliac Joint Auricular articular surfaces

Sacroiliac Joint Sacroiliac joint Anterior sacroiliac ligaments Posterior sacroiliac ligaments

Os Coxae Hemipelvis is composed of the ilium, ischium and pubis with articulations centered in acetabulum – triradiate articulation Fusion of the 3 bones is complete between 20 and 25 years of age Articulations of 3 bones - ilium, ischium & pubis- radiate from acetabulum – triradiate articulation Acetabulum deep compared to glenoid fossa in order to provide stability/weightbearing

Tri-radiate Articulation Triradiate cart is radio lucent

Joints of the Free Limb Hip Polyaxial ball and socket joint: Felxion/extension Adduction/abduction Medial/lateral rotation Acetabulum deep compared to glenoid fossa Acetabular labrum deepens joint Capsular ligaments: iliofemoral, ischiofemoral, pubofemoral Iliofemoral lig. Pubofemoral lig. Ischiofemoral lig. Ligament of head of femur

Joints of the Free Limb Knee Tibiofemoral artic. Patelofemoral artic. Modified hinge joint Tibiofemoral artic. Patelofemoral artic. Femur Tibia Patella Consists of tibiofemoral and patelofemoral articulations

Joints of the Free Limb Ankle (talocrural) joint Hinge joint 1 axis of movement: Dorsiflexion/plantarflexion

Joints of the Free Limb Foot Interphalangeal joints: Distal Proximal metatarsophalangeal joints Inversion/eversion occurs at subtalar (talocalcaneal) joint

Vasculature of the Lower Limb

Superficial Veins Great saphenous v. Small saphenous v.

Arterial Blood Supply Internal Iliac a Femoral a Superior gluteal a External Iliac a Femoral a Popliteal a Anterior Posterior tibial a tibial aa dorsalis med/lat pedis plantar a Internal Iliac a Superior gluteal a Inferior gluteal a Obturator a Primary blood supply to lower limb is from external iliac a Internal iliac supplies proximally - gluteal and prox adductor compartment Collateral circulation - anastomotic channels between internal and external

Medial & lateral femoral circumflex arteries Deep Femoral Artery During growth, aa cannot cross avascular epiphiseal plate but reach head of femur in periosteum Primary supply to head of femur is from medial and lat femoral circumflex aa – artery to the head of femur is inconsistently present and not primary supply Medial & lateral femoral circumflex arteries

Fascial Compartments

Fascia of the Lower Limb Gluteal Fascia Fascia Lata Crural Fascia

Fascial Compartments of the Thigh Fascial septa divide limb into compartments anterior compartment medial compartment posterior compartment Anterior compartment Lateral intermuscular septum, posterior intermuscular septum and subsartorial fascia/septum Medial (adductor) compartment Posterior compartment Fascia Lata

Fascial Compartments of the Leg anterior compartment Anterior crural compartment Lateral crural compartment Posterior crural compartment lateral compartment posterior compartment anterior Interosseous septum, anterior intermuscular septum, posterior intermuscular septum lateral Superficial & deep posterior crural compartments Crural Fascia posterior

Lumbosacral Plexus

Innervation of the Lower Limb: Lumbosacral Plexus (L1 - S3)

Lumbosacral Plexus L1 - S3

Gluteal innervation: Superior gluteal n (L4,5, S1): gluteus medius m. gluteus minimus m. tensor fascia lata Inferior gluteal n (L5, S1,2): gluteus maximus m. N to obturator internus (L5, S1, 2): oburator internus superior gemellus Nerve to quadratus femoris (L4,5, S1): inferior gemellus quadratus femorus

Compartmental Innervation Posterior compartment Of the Free Limb Anterior compartment Medial compartment Posterior compartment Lateral compartment Thigh Leg Foot

Anterior (extensor) compartment of the thigh Innervation: femoral nerve anterior anterior

Medial (adductor) compartment of the thigh Innervation: obturator nerve* medial *Adductor Magnus innervated by both obturator n and tibial division of sciatic n medial

Posterior compartment of the thigh Hamstring mm: arise from ischial tuberosity & are innervated by tibial division of sciatic n. Innervation: Tibial division of sciatic nerve Except short head of biceps femoris: common fibular division of sciatic nerve Note that sciatic nerve divides into tibial n and common fibular n posterior

Posterior compartment of the leg Innervation: tibial n. posterior Tibial n continues posteriorly while common fibular n goes around fibular head to supply lateral and anterior compartments Superficial posterior crural compartment Deep posterior crural compartment

Plantar surface of the foot Innervation: Medial & lateral plantar nerves

Innervation of intrinsic muscles of the foot Medial plantar n •flexor digitorum brevis •flexor hallucis brevis •abductor hallucis m •1st lumbrical Lateral plantar n •abducator digiti minimi •quadratus plantae •2nd, 3rd & 4th lumbricals •adductor hallucis •Flexor digiti minimi •dorsal & plantar interossei

Common fibular nerve Nerve supply to the lateral and anterior crural compartments anterior lateral anterior lateral

Lateral crural compartment: Superficial fibular nerve Fibularis longus Fibularis brevis lateral

Anterior crural compartment: Deep fibular nerve Tibialis anterior m. Extensor hallucis longus m. Extensor digitorum longus m. Fibularis tertius m. anterior

Dorsum of the foot: deep fibular nerve Extensor hallucis brevis Extensor digitorum brevis

Compartmental Innervation of Free Limb Anterior compartment Medial compartment Posterior compartment Lateral compartment Tibial division of sciatic n. * Thigh Femoral n. Obturator n.* *adductor magnus - obturator n and tibial n *short head of biceps femoris - common fib. division of sciatic n. Leg Superficial fibular n. Deep fibular n. Tibial nerve Foot Deep fibular n. Tibial n. (medial and lateral plantar n.)

Dermatomes Key dermatomes* thumb - C6 5th digit of hand - C8 nipples - T4 umbilicus - T10 hip crease - L1 great toe - L4 5th toe - S1 *area of skin supplied by a dorsal nerve root

Key dermatomes* of the Lower Limb umbilicus - T10 hip crease - L1 great toe - L4 5th toe - S1 *area of skin supplied by a dorsal nerve root

Cutaneous Nerve Supply to the Lower Limb

References Clemente, C. 1997 Anatomy: A Regional Atlas of the Human Body, 4th edition. Lippincogtt Williams & Wilkins. Rinabesm C,H, 1972. Cunningham’s Textbook of Anatomy, 11th edition. Oxford University Press. Rosse, C & Gaddum-Rosse, P. 1997. Hollinshead’s Textbook of Anatomy 5th edition. Lippincott-Raven Schuenke, M et al, 2006 Thieme Atlas of Anatomy: Musculoskeletal System. Thieme. Slaby, F., et al. 1994. Gross Anatomy in the Practice of Medicine. Lea & Febiger.