Anatomy and Function of Major Joints and Muscles

Pelvic girdle

Made up of SI joint and 2 innominate bones (unnamed).

Innominate

Made up of 3 fused bones: Ilium, ischium, pubis.

Hip joint

Articulation between the head of the femur and the acetabulum (socket) of the pelvis.

Ilium

Wing-shaped superior portion of innominate.

Iliac crest

Long ridge of bone that marks superior border of ilium.

ASIS

Tip of iliac crest.

AIIS

Inferior to ASIS.

PSIS

Posterior tip of the iliac crest.

PIIS

Small bony prominence located inferior to PSIS, marking superior tip of greater sciatic notch.

Iliac fossa

Smooth, concave, anterior surface of ilium.

Greater sciatic notch

Semicircular space between PIIS and ischial spine providing space for sciatic nerve to exit pelvis.

Ischium

On posterior inferior aspect of innominate.

Ischial spine

Posterior projection of bone marking inferior aspect of greater sciatic notch.

Ischial tuberosity

Bumpy projection from posterior inferior aspect of ischium.

Pubis

Is composed of two rami, superior and inferior ramus, that coalesce anteriorly to form pubic crest.

Pubis symphysis

Junction between pubic crest of each innominate, completing anterior 'ring' of pelvis.

Obturator foramen

Large circular opening formed by pubic rami and ischium, covered by obturator membrane.

Acetabulum

Cup-shaped structure enclosing head of femur, formed by combination of all 3 pelvis bones.

Lunate surface

Horseshoe-shaped superior surface of acetabulum, heavily lined with articular cartilage.

Acetabular fossa

Depression deep within floor of acetabulum.

Femur

Longest bone in body.

Femur head

Contains depression called fovea which accepts ligamentum teres.

Femur neck

Connects head to shaft, bordered superior-laterally by greater trochanter.

Greater trochanter

Projection of bone that extends laterally from near junction of femoral neck and shaft.

Lesser trochanter

Sharp posterior-medial projection of bone.

Intertrochanteric crest

Ridge of bone connecting posterior aspect of greater and lesser trochanter.

Intertrochanteric line

Courses anteriorly between greater and lesser trochanters.

Trochanteric fossa

Small pit on posterior medial side of greater trochanter, difficult to palpate.

Linea aspera

Line of slightly raised bone that courses along much of posterior side of femur.

Pectineal line

Small crest of bone running from lesser trochanter to superior aspect of Linea aspera.

Gluteal tuberosity

Arises from superior-lateral portion of Linea aspera.

Adductor tubercle

Raised portion of bone located just proximal to medial epicondyle.

Iliofemoral Joint

Structural components: Femoral head and acetabulum; Joint classification: Synovial ball and socket.

Sacroiliac Joint (SIJ)

Structural components: Sacrum and ilium; Joint classification: Synovial joint.

Hip flexors

Muscles including Iliopsoas, Rectus femoris, Sartorius, Tensor fascia latae.

Hip extensors

Muscles including Glute max, Semitendinosus, Semimembranosus, Biceps femoris- long, Adductor magnus- extensor head.

Hip abductors

Muscles including Glute med, Glute max, Tensor fascia latae.

Hip adductors

Muscles including Pectineus, Adductor brevis, Gracilis, Adductor longus, Adductor magnus.

Hip ER

Muscles including Glute max, Sartorius, Piriformis, Gemellus superior and inferior, Obturator internus and externus, Quadratus femoris.

Hip IR

Muscles including Glute med, Glute min, TFL.

Arthrokinematics

Iliofemoral joint movement: Acetabulum: concave; Femoral head: convex; Roll and glide: opposite.

Osteokinematics

3 degrees of freedom: Sagittal: flexion/extension; Frontal: abduction/adduction; Transverse: ER/IR.

Nutation/counternutation

Movement is very limited in all planes and generally decreases beyond 30s.

Normal end feels

Hip flexion end feel: soft; Hip extension end feel: firm; Hip ER end feel: firm; Hip IR end feel: firm; Hip abduction end feel: firm; Hip adduction end feel: firm.

Capsular pattern for hip

Internal rotation most limited followed by flexion, followed by abduction: IR > Flex > ABD.

Tibiofemoral Joint

Structural components of the joint: Femur (medial & lateral condyles) and tibia (medial & lateral articular surface).

Joint Classification of Tibiofemoral Joint

Synovial bicondylar joint.

Patellofemoral Joint

Structural components of the joint: Femur (patellar facets) & patella (medial and lateral facets).

Joint classification of Patellofemoral Joint

Synovial plane joint.

Patella

The largest sesamoid bone in the body.

Intercondylar groove

Smooth area between femoral condyles for patella articulation.

Medial epicondyle

Bony projection on medial femoral condyle.

Lateral epicondyle

Bony projection on lateral femoral condyle.

Intercondylar notch

Passageway for cruciate ligaments on distal femur.

Medial condyle

Projection of femur articulating with medial tibia.

Lateral condyle

Projection of femur articulating with lateral tibia.

Tibial plateau

Flattened superior surfaces of tibial condyles.

Intercondylar eminence

Double-pointed bone projection between tibial condyles.

Tibial tuberosity

Protrusion on anterior aspect of proximal tibia.

Proximal fibula

Long slender bone alongside the tibia.

Fibular head

Rounded portion of fibula articulating with tibia.

Superior pole of patella

Base accepting quadriceps tendon attachment.

Inferior pole of patella

Apex accepting patellar ligament attachment.

Q Angle

Angle of quadriceps pull relative to knee.

Average Q Angle (Males)

Typical range: 10-13 degrees.

Average Q Angle (Females)

Typical range: 15-17 degrees.

Knee screw home mechanism

Knee externally rotates to lock in extension.

Full extension

Knee position at 0 degrees flexion.

Tibiofemoral joint

Joint between tibia and femur.

Patellofemoral joint

Joint between patella and femur.

Knee Extensor Mechanism

Tendons and ligaments stabilizing knee extension.

Normal End Feel

Resistance felt at end of joint motion.

Capsular Pattern

Specific limitations of joint movement due to capsule.

Talocrural Joint

Main ankle joint classified as synovial hinge.

Subtalar Joint

Joint between talus and calcaneus allowing inversion/eversion.

Pronation

Movement combining eversion, abduction, and dorsiflexion.

Supination

Movement combining inversion, adduction, and plantarflexion.

Dorsiflexion

Ankle movement raising the foot upwards.

Plantarflexion

Ankle movement pointing the foot downwards.

Cervical Vertebrae

Seven smallest and most mobile vertebrae.

Atlas (C1)

First cervical vertebra supporting the skull.

Axis (C2)

Second cervical vertebra allowing head rotation.

Craniocervical Region

Neck area with three major articulations.

Atlanto-Occipital Joint

Joint between occipital condyles and atlas.

Atlanto-Axial Joint

Joint allowing rotation between C1 and C2.

Intervertebral Disc

Cartilaginous structure absorbing spinal forces.

Zygapophyseal Joints

Synovial joints between vertebrae facilitating movement.

Uncovertebral Joint

Joint guiding sagittal movements in cervical spine.

Fibular Notch

Concave area of tibia articulating with fibula.

Medial Malleolus

Bone projection from distal tibia.

Lateral Malleolus

Bone projection from distal fibula.

Distal Tibiofibular Joint

Joint allowing minimal movement between tibia and fibula.

End Feel for Dorsiflexion

Firm resistance felt at maximum ankle dorsiflexion.

End Feel for Plantarflexion

Firm resistance felt at maximum ankle plantarflexion.

Lower cervical spine

C2-C7

Upper cervical spine

C0-C2

Capital flexion

Chin tuck

Capital extension

Head tilt

Retraction

Upper cervical flexion and lower cervical extension

Protraction

Upper cervical extension and lower cervical flexion