Muscles
- The hip is a multiaxial joint allowing movement in all 3 cardinal planes
- Functionally the muscles acting at the hip joint are divided into their functional groups:
- Flexors
- Extensors
- Adductors
- Abductors
- Medial Rotators
- Lateral Rotators
- Most muscles however produce more than a single cardinal movement
Hip Flexion
- The main hip flexors are 2 muscles situated in the posterior aspect of the abdomen
- Collectively known as Iliopsoas
- Separated from the superior pubic ramus/anterior hip by the iliopsoas bursa
- Action - flexion of the hip joint, anterior pelvic tilt and lumbar flexion
- Assisted by:
- Rectus Femoris (Quadriceps)
- Sartorius
- Tensor Fascia Lata (Abductors)
- Pectineus (Adductors)
- Anatomically and functionally all belong to other muscle groups but have secondary role as hip flexors
- Rectus Femoris:
- O: Straight head from AIIS, reflected head from groove above the acetabulum
- I: Base of patella
- A: Knee extension/hip flexion
- Sartorius:
- O: ASIS
- I: Pes Anserine insertion - medial tibial shaft
- A: Hip Flexion / Lateral rotation, Knee Flexion / Medial Rotation
- NS: Femoral nerve L2, 3 & 4
- Tensor Fascia Lata:
- O: Outer lip of iliac crest – ASIS to tubercle
- I: ITB
- A: Hip Abduction / Flexion / Medial Rotation
- NS: Superior gluteal nerve L4, 5 & S1
- Pectineus:
- O: Superior Pubic Ramus
- I: Pectineal line on Femur
- A: Flexion/adduction of hip - may assist with medial rotation
- NS: Femoral nerve L2/3 and Obturator nerve L2/3
Hip Extension
- Very powerful movement brought about by:
- Gluteus Maximus
- Large, powerful, quadrilateral shaped muscle forming contour of buttock
- Hamstring Muscles:
- Semimembranosus
- Semitendinosus
- Biceps Femoris
- (3 fusiform muscles forming the posterior compartment of the thigh - span both the hip and knee therefore will have dual action)
- Actions include hip, extension and lateral rotation
- When working on a fixed femur will assist with bringing the pelvis up from flexion (muscles working with reversed attachment)
- Upper fibres can assist with abduction of the hip
- NS: Inferior gluteal nerve L5, S1 & 2
The Compartments of the Thigh
- As with any other body segment the thigh region is divided into compartments containing functional groups
- Divisions are made by the intermuscular septa
- 3 compartments to consider:
- Anterior
- Posterior
- Medial
The Hamstrings
- Found in the posterior compartment of the thigh:
- Semimembranosus:
- O: Ischial tuberosity
- I: Posterior aspect of medial condyle of tibia – forms posterior oblique ligament of knee
- Semitendinosus:
- O: Ischial tuberosity
- I: Pes anserine insertion – medial shaft of tibia
- Actions – both extend hip and flex/medially rotate the knee
- NS: tibial division of sciatic nerve L5, S1 & 2
- Biceps femoris
- O: Long head – from ischial tuberosity
- Short head – from lower ½ of linea aspera
- I: Head of fibula
- Action: extension of hip, flexion and lateral rotation of knee
- NS: Tibial division of sciatic nerve (long head), Common Peroneal division of sciatic nerve (short head), L5, S1 & S2
Hip Adduction
- Relatively weak movement brought about by the muscles of the medial compartment of the thigh
- Muscles include:
- Adductor Longus
- Adductor Brevis
- Adductor Magnus
- Gracilis
- Pectineus
Medial Compartment
- Contains the Adductor Group:
- Gracilis
- Pectineus
- Adductor Longus, brevis and magnus
- All arise from ischial tuberosity & ramus and pubis and rami
Gracilis and Pectineus
- Most medial adductor
- O : Body of pubis, inferior pubic ramus and adjacent ischial ramus
- I: Pes anserine insertion between sartorius and semitendinosus
- A: Adduction of the hip, weak flexor and medial rotator of the knee
- NS: Obturator nerve (L2, 3)
- For details of pectineus see above
Adductor Longus
- Most anterior of main adductor group
- O: Via short rounded tendon from anterior aspect of body of pubis
- I: Middle ½ of linea aspera
- A: Adductor and flexor of the hip
- NS: Obturator nerve L2,3 and 4
Adductor Brevis
- Middle and smallest muscle of main adductor group
- O: Via flat attachment to body of pubis and inferior pubic ramus
- I: Upper ½ of linea aspera and lower part of pectineal line
- A: Adductor of the hip
- NS: Obturator nerve L2,3 and 4
Adductor Magnus
- Most posterior and largest of main adductor group
- O: Via large fleshy attachment to ischial tuberosity (ischial head) and ischiopubic ramus (adductor head)
- I: Whole of linea aspera, medial supracondylar ridge and adductor tubercle (ischial portion) – note adductor hiatus
- A: Adductor and extensor of the hip
- NS: Obturator nerve (L2, 3 & 4) and tibial nerve (L4, 5)
Abductors/Medial rotators of the Hip
- Abductors
- Gluteus maximus (upper fibres)
- Gluteus medius
- Gluteus minimus
- Tensor Fascia Lata
- Medial Rotators
- Gluteus medius
- Gluteus minimus
- Tensor Fascia Lata
- (Psoas major and iliacus - some debate over its role)
- Note dual role of these muscles as abductors and medial rotators
Abductors of the Hip Joint
- All arise from the gluteal surface of the innominate bone
- Gluteus maximus (predominantly a hip extensor) is the most posterior & superficial
- Gluteus medius lies deep & anterior to G max
- Gluteus minimus lies deep & anterior to medius
- Tensor fascia lata (see above) lies superficial & anterior to minimus
Gluteus Maximus
- Predominantly a hip extensor
- Secondary role as a lateral rotator and abductor (upper fibres) or adductor (lower fibres)
Gluteus Medius, Minimus & TFL
Tensor Fascia Lata (TFL)
- O : Outer lip of iliac crest - ASIS to tubercle
- I : Between 2 layers of ilio-tibial tract
Gluteus Medius
- O : Gluteal surface of ilium between posterior and anterior gluteal lines
- I : Via a flat tendon on upper lateral aspect of greater trochanter (roughened area)
Gluteus Minimus
- O : Gluteal surface of ilium between anterior and inferior gluteal lines
- I : Via a small thickened tendon into small depression on ant/sup aspect of greater trochanter
- Note presence of trochanteric bursa separating tendon of gluteus medius from greater trochanter
Abductors/Medial Rotators
Actions
- All act as abductors and medial rotators of the hip joint (gluteus minimus, TFL and anterior fibres of gluteus medius)
- Note direction of fibres in relation to hip joint axis
- Tensor fascia lata also acts as a hip flexor
Function
- Most important role is during weight bearing phase of gait to maintain a level pelvis
Nerve Supply
- Superior gluteal nerve L4, 5 and S1
Lateral Rotators
- In addition to Gluteus maximus note deep group of muscles
- Act as lateral rotators of the neutral hip and abduct the flexed hip
- In addition to the above there is a 6th lateral rotator…Obturator externus
- Note their relative positions, courses and their relationship to the Sciatic nerve
- Make brief notes on their attachments