Lecture 12 - Abdominal and Back Muscles Flashcards
movements of the spine
- > Flex/Extension
- > lateral flex/extension
- > rotation of head and neck
- > rotation of upper trunk
possible motions of the cervical spine (and its attachments to the skull)
Fle/extension
Lateral flexion
rotation
These motions primarily occur at the atlanto-occipital joint and the atlanto-axial joint
muscles of the neck
scalenes
sternocleidomastoid
O/I/I/A of sternocleidomastoid
Origin
- > manubrium and medial portion of the clavicle
Insertion
- > mastoid process of the temporal bone, superior nuchal line
Innervation
- > accessory erve (CN 11)
Action
(Unilaterally) contralateral cervical rotation, ipsilateral flexion of the cervical spine
(bilaterally) cervical flexion, assis with forced exhalation by elevating the sternum
O/I/I/A of scalenes
3 muscles (Ant, middle, post)
Origin
- > cervical verts (2-7)
Insertion
- > 1st and 2nd ribs
Innervation
- > cervical nerves (C3-6)
Actions
- > elevation of the first and second ribs. lateral flexion of the neck, and assists with forced inhalation
muscles of the back
- > Multifidus
- > rotatores
- > quadratus lumborum
muscles of the abdominal wall
- > rectus abdominis
- > internal obliques
- > external obliques
- > transvers abdominus
- > quadratus lumborum
characteristics of the multifidus
- > it spans only a few verts
- > its function is spinal extension BUT forces affect only local areas of the spine so it only extends a portion of the spine
characteristics of the rotatores
- > usually described as “rotators” of the spin but they’re so small that their contribution to twisting is limited
- > instead, they have a proprioception function
O/I/I/A of quadratus lumborum
Origin
- > illiac crest and illiolumbar ligament
Insertion
- > base of 12th rib and transverse processes of the lumbar verts
Innervation
- > ventral rami of T12-L4
Actions
(unilaterally) lateral flexion of the vert column
(bilaterally) depression of the rib cage
special functions of quadratus lumborum
research has shown that the length of the muscle remains fairly constant when activated so it is though to help stabilize lumbar spine
O/I/I/A of rectus abdominus
Origin
- > crest of the pubis
Insertion
- > costal cartlidges of ribs 5-7, xiphoid process
Innervation
- > throaco-abdominal nerves (T7-11_ and subcostal nerve (T12)
Action
- > flexion of the lumbar spine
why are the abs segmented and not one long muscle
note the directions of the internal vs external obliques
O/I/I/A of the external obliques
Origin
- > ribs 5-12
Insertion
- > illiac crest, pubic tubercle, linea alba
Innervation
- > thoracoabdominal nerves (T7-11) and subcostal nerve (T12)
Action
- > contralateral rotation of torso
O/I/I/A of internal obliques
Origin
- > inguinal ligament, iliac crest, and lubodorsal fascia
Insertion
- > linea alba, and ribs 10-12
Innervation
- > thoracoabdominal nn (T7-T11) subcostal nerve (T12), illiohypogastric n (L1) and illioinguinal n (L1)
Actions
- > (unilaterally) ipsilateral trunk rotation
- > (bilaterally) compresses abdomen
O/I/I/A of transverse abdominus
Origin
- > illiac cres, inguinal ligament, thoracolumbar fascia, and costal cartilage 7-12
Insertion
- > xiphoid process, linea alba, pubic crest
Innervation
- > thoracoabdominal n, subcostal n, illiohypogastric N and illioinguinal N
Actions
- > compress abdominal cavity
movements of the spine summary
