Functional Anatomy Exam 2 Muscles

Anterolateral (trunk rotators)

External oblique

Internal oblique

Transverse Abdominus

Anterior Trunk Flexor

Rectus Abdominus

Intrinsic (Deep) Back Muscles

Splenius (Capitis + Cervicis)

Erector Spinae (iliocostalis, longissimus, spinalis)

Transversospinalis (semispinalis, multifidus, rotatores)

Suboccipital (rectus capitis, posterior major + minor, obliquus capitis superior + inferior)

Splenius (Capitis + Cervicis)

O: Lower cervical + upper thoracic spinous processes

I: mastoid process + lateral base of cranium (capitis) & cervical transverse processes (cervicis) 

A: bilateral (extension of head + neck, contributes to extension of atlanto-occipital joint)

Unilateral (ipsilateral lateral flexion & rotation of head/neck, turning head right, rotation at cervical vertebrae & atlanto-axial joint)

Erector Spinae (iliocostalis, longissimus, spinalis) that extend from lower back region to various attachments superiorly)

O: Sacrum, iliac crest, thoracolumbar fascia, lower-level spinous process

I: ribs, upper-level spinous processes, mastoid

A: bilateral (vertebral column extension)

Unilateral (ipsilateral vertebral column lateral flexion)

Transversospinalis (semispinalis, multifidus, rotatores)

Location: Deep to erector spinae

Semispinalis (prominent in cervical region)

Multifidus (prominent in lumbar region)

Rotatores (deep to all layers)

O: transverse processes

I: laminae of more superior vertebrae (various course over 1-6 levels)

A: Bilateral (contribute to overall vertebral column extension)

Unilateral (contralateral rotation of vertebral column)

Quadratus Lumborum

Located: deep to intrinsic back layers, contributes to posterior abdominal wall

O: iliac crest, lumbar transverse processes, 12th rib

I:Transverse processes of the lumbar vertebrae (L1-L5)

Inferior border of the 12th rib 

A: lateral flexion, stabilizes 12th rib

N: ventral rami T12-L4

Suboccipital (rectus capitis, posterior major + minor, obliquus capitis superior + inferior)

four small muscles form triangular space from their attachments to the

C2 spinous process

C1 transverse process

base of skull

N: suboccipital nerve (dorsal ramus of C1)

Suboccipital continued Need to know? not in slide

• Rectus capitis posterior major: Extends and rotates the head

Rectus capitis posterior minor: Extends the head and rotates

• Obliquus capitis superior: Rotates and laterally flexes the head

• Obliquus capitis inferior: Rotates and laterally flexes the head

• Obliquus capitis superior: 

  • Origin: Transverse process of the atlas (C1) 

  • Insertion: Lateral part of the inferior nuchal line of the occipital bone 

• Obliquus capitis inferior: 

  • Origin: Spinous process of the axis (C2) 

  • Insertion: Transverse process of the atlas (C1) 

• Rectus capitis posterior major: 

  • Origin: Spinous process of the axis (C2) 

  • Insertion: Medial part of the inferior nuchal line of the occipital bone 

• Rectus capitis posterior minor: 

  • Origin: Posterior tubercle of the atlas (C1) 

  • Insertion: Medial part of the inferior nuchal line of the occipital bone 

Anterior Muscles with Actions on Trunk

Rectus Abdominis

O: pubic symphysis + pubic crest

I: Xiphoid Process + 5th-7th costal cartilages

A: thoracolumbar flexion, compression of abdominal cavity, stabilizes tilt of pelvis (anti-anterior tilt)

N: anterior rami of T7-T12 (intercostal nn)

External + Internal Oblique and transverse abdominus ???

no info in slide just name

Psoas Major + Iliacus

PM

O: Lumbar vertebra to

lesser trochanter

N: ventral ramus L2

Psoas Major Muscle Anterior Rami of L1-L3

Iliacus

O: Iliac fossa to lesser

trochanter

N: Femoral nerve

Iliopsoas: hip flexion

Sternocleidomastoid

O: sternum + clavicle

I: mastoid process

A: Unilateral (ipsilateral lateral flexion)

Bilateral (head + cervical neck flexion)

N:spinal accessory

Prevertebral Muscles

Longus capitus mm.:

-Basilar occipital bone: upper cervical transverse process

A: bilateral (atlanto-occipital flexion, stabilize cervical vertebrae w/ posterior forces)

Unilateral (lateral cervical flexion)

N: anterior cervical rami (C1-C6)

Prevertebral Muscles

Longus colli mm.:

-Upper: lower cervical vertebral muscles

A: bilateral (stabilize cervical vertebrae w/ posterior forces)

Unilateral (lateral cervical flexion)

N: anterior cervical rami (C1-C6)

Scalene

O: cervical transverse processes C3-C7

I: anterior + middle scalene (1st rib)

anterior scalene (2nd rib)

A: ipsilateral (ipsilateral lateral cervical flexion)

bilateral (elevates thoracic cage during forced respiration)

N: anterior cervical rami (C1-C6)

Gluteal Muscles

Piriformis

Superior Gemellus

Inferior Gemellus

Obturator Internus

Quadratus Femoris

Gluteus Minimus

Piriformis

O: anterior surface of sacrum between 2nd and 4th sacral vertebrae, gluteal surface of ilium near margin of greater sciatic notch

I: superior border of greater trochanter of femur, medial side of insertion point

A: lateral rotation of hip, abduction of thigh, help stabilize hip joint

N: S1, S2

Superior Gemellus

O: gluteal (posterior) surface of the ischial spine of the pelvis

I:medial surface of the greater trochanter of the femur

A: lateral rotation of thigh, abducts thigh, stabilizes hip

N: L5-S1

Inferior Gemellus

O: ischial tuberosity

I:medial surface of the greater trochanter of the femur

A:lateral rotation of hip, abduction of thigh, help stabilize hip joint

N: L4-S1

Obturator Internus

O: internal surface of pelvic bone surrounding obturator foramen

I: greater trochanter of femur

A: lateral hip rotation, holds head of femur in acetabulum

N:obturator nerve (L4-S3)

Quadratus Femoris

O: Lateral border of the ischial tuberosity, on the posterior surface of the pelvis

I:Quadrate tubercle on the posterior intertrochanteric crest of the femur

A: lateral rotation of hip, abduction of thigh, help stabilize hip joint

N: L4- S1

Gluteus Minimus

O: Gluteal surface of the ilium, between the anterior and inferior gluteal lines, Edge of the greater sciatic notch

I:Anterior surface of the greater trochanter of the femur, Lateral aspect of the hip joint capsule

A: lateral rotation of hip, abduction of thigh, help stabilize hip joint

N:superior gluteal nerve (L4-S1)