the pelvis and hip

The Pelvis and Hip The Pelvis and Hip

Nervous SystemNervous System

Highly complexControls, stimulates, and coordinates all

other body systemsCan be divided:

– Central Nervous System (CNS)– Peripheral Nervous System (PNS)– Autonomic Nervous System (ANS)

THE NERVOUS SYSTEMTHE NERVOUS SYSTEM

Peripheral Nervous System Peripheral Nervous System (PNS)(PNS)

Composed of all the nervous tissue outside the vertebral canal

Begins at the anterior horn of the spinal cord

Branches of the Spinal Nerves Branches of the Spinal Nerves

Posterior primary rami innervate the deep muscles of the back and the skin covering these muscles

Spinal nerve continues as the anterior primary ramus

Branches of the Spinal Nerves Branches of the Spinal Nerves (cont(cont’’d)d)

Anterior primary rami innervate all muscles and skin not innervated by the posterior primary rami

Plexus FormationPlexus Formation

Anterior branches of spinal nerves in thoracic region give rise to intercostal nerves (not a plexus)

Spinal nerves in other regions combine to form complex networks called plexuses

Plexus Formation Plexus Formation (cont(cont’’d)d)

1. Cervical Plexus - C1 - C4– Innervates neck muscles

2. Brachial Plexus - C5 - T1– Innervates UE muscles

3. Lumbosacral Plexus- L1 - S5– Innervates LE muscles– Lumbar portion- L1-L4

Supplies mostly the thigh

– Sacral portion - L5-S5 Supplies mostly the leg

and foot

IliopsoasIliopsoas Actually two muscles

– Separate origin– Common insertion

O: Iliacus - iliac fossaPsoas major - anteriorand lateral surfaces T12-L5

I: Lesser trochanterA: Hip flexionN: Iliacus - Femoral Nerve

Psoas Major - L2-3

Rectus FemorisRectus Femoris

Part of the quadriceps Two-joint muscle crosses hip

and knee anteriorly

O: Anterior inferior iliac spine

I: Tibial tuberosity

A: Hip flexion, Knee extension

N: Femoral Nerve, L2-L4

SartoriusSartorius

Longest muscle in the body Straplike muscle “Tailor’s Muscle”

O: Anterior superior iliac spine

I: Proximal medial aspect of tibia

A: Hip flexion, abduction, lateral rotation

N: Femoral Nerve, L2-L3

PectineusPectineus Located

– Medial to the iliopsoas– Lateral to the adductor

longus

O: Superior ramus of pubis

I: Pectineal line of femur

A: Hip flexion and adduction

N: Femoral Nerve, L2-L4

Adductor Longus (A)Adductor Longus (A)

Most superficial– Tendon palpable in anterior-

medial groin

O: PubisI: Middle 1/3 linea

asperaA: Hip adductionN: Obturator Nerve,

L3-L4

Adductor Brevis (B)Adductor Brevis (B) Shorter Deep to adductor longus Superficial to adductor magnus

O: Pubis

I: Pectineal line and proximal linea aspera

A: Hip adduction

N: Obturator Nerve, L3-4

Adductor Magnus Adductor Magnus (C)(C)

Largest, most massive, and deepest

Opening or hiatus in distal attachment between linea aspera and adductor tubercle– Femoral artery and vein pass

through opening– After femoral artery and vein

pass through, their names change to popliteal artery and vein

Adductor MagnusAdductor Magnus (C)(C)

(cont(cont’’d)d)

O: Ischium and pubis

I: Entire linea aspera and adductor tubercle

A: Hip adduction, extension

N: Obturator and sciatic nerve (L3-L4)

GracilisGracilis

Two-joint muscle

O: Pubis

I: Anterior medial surface of proximal end of tibia

A: Hip adduction

N: Obturator Nerve, L2-L3

Gluteus MaximusGluteus Maximus Large, one-joint, quadrilateral-shaped,

thick, superficial muscle Some fibers attach to iliotibial band

O:Posterior sacrum and ilium

I: Posterior femur distal to greater trochanter

A: Hip extension, hyperextension, lateral rotation

N: Inferior gluteal nerve, L5, S1, S2

Deep RotatorDeep RotatorMusclesMuscles

Number = 6, deep, mostly posterior muscles spanning the hip joint in a horizontal direction

Laterally rotate the hip

O: Posterior sacrum, ischium, pubis

I: Greater trochanter area

A: Hip lateral rotation

Deep Rotator MusclesDeep Rotator Muscles

Muscle Proximal Attachment Distal Attachment Innervation

Obturator externus Rami of pubis and ischium Trochanteric fossa Obturator nerve

Obturator internus Rami of pubis and ischium Greater trochanter Nerve to obturatorinternus

Quadratus femoris Ischial tuberosity Intertrochanteric crest Nerve to quadratus

femoris

Piriformis Sacrum Greater trochanter S1, S2 segments

Gemellus superior Ischium Greater trochanter Nerve to obturator

internus

Gemellus inferior Ischial tuberosity Greater trochanter Nerve to quadratus

femoris

Deep Rotator Muscles Deep Rotator Muscles (cont(cont’’d)d)“Piece Goods Often Go On Quilts”

Anatomical order superior to inferior– Piriformis– Gemellus superior– Obturator internus– Gemellus inferior– Obturator externus– Quadratus femoris

HamstringsHamstrings

Posterior thigh muscles Two joint muscles except

short head of biceps femoris Ischial tuberosity - common

origin

A. Semitendinosus

B. Biceps femoris

C. Semimembranosus

SemimembranosusSemimembranosus (C)(C)

O: Ischial tuberosity

I: Posterior surface of medial condyle of

tibia

A: Extend hip, flex knee

N: Sciatic nerve

L5, S1, S2

Semitendinosus Semitendinosus (A)(A)

O: Ischial tuberosity

I: Anteromedial surface of proximal tibia

A: Extend hip, flex knee

N: Sciatic nerve

L5, S1, S2

Biceps Femoris Biceps Femoris (B)(B)

O: Long head: Ischial tuberosityShort head: lateral lip

linea aspera

I: Fibular head

A: Long head: Extend hip, flex knee

Short head: Flex knee

N: Long head: Sciatic nerve, S1-S3

Short head: Common peroneal nerve, L5-

S2

Gluteus MediusGluteus Medius

Triangular shaped

O: Outer ilium

I: Greater trochanter

A: Hip abduction

N: Superior gluteal nerve

L4, L5, S1

Gluteus MinimusGluteus Minimus Deep and inferior to the gluteus

medius

O: Lateral ilium I: Anterior surface of the

greater trochanterA: Hip abduction, internal

rotationN: Superior gluteal nerve

L4, L5, S1

Reversal of Muscle FunctionReversal of Muscle Function

When you stand on one leg:– Distal segment (femur) becomes more stable than the

proximal segment (os coxae)– Origin moves toward insertion

Without contracting - pelvis would drop on opposite side

Weakness “Trendelenberg gait”– If weak right hip abductors, stand on right, left side drops

Reversal of Muscle Reversal of Muscle FunctionFunction (cont(cont’’d)d)

A. In reversal of muscle function, the right hip abductors contract to keep the pelvis steady when the left leg is lifted.

B. When right hip abductors are weak, the left side of the pelvis drops.

Tensor Fascia LataeTensor Fascia Latae

Short muscle Long tendinous attachment

O: Anterior superior iliac spine

I: Lateral condyle of tibia

A: Combined hip flexion and abduction

N: Superior gluteal nerve

L4-L5

Force-Couple for anterior tilt

Compensation for tight hip flexors

Stabilizing role of abdominalsStabilizing role of abdominals

Poor stabilization of abdominals

Bilateral cooperation of adductorsBilateral cooperation of adductors