Muscles Flashcards
Action of Longus Colli
Bilaterally flexes the neck
Attachments of Sternocleidomastoid
Sternal head: anterosuperior surface of manubrium sterni.
Clavicular head: superior surface of medial two thirds of the clavicle.
Distal: lateral surface of mastoid process of temporal bone and a thin aponeurosis to lateral third of superior nuchal line of occipital bone.
Actions of Sternocleidomastoid
Ipsilateral side flexion of the neck.
Contralateral rotation of the head.
Bilateral flexion of the neck against resistance.
Posterior fibres extend the head at the Atlanta-occipital joint.
Raise the clavicle and manubrium sterni when head and neck are fixed.
Attachments of Scalenus Anterior
Proximal: anterior tubercles of transverse processes of C3-C6.
Distal: scalene tubercle on inner border of 1st rib.
Actions of Scalenus Anterior
Ipsilateral side flexion of the neck.
Contralateral rotation of the head.
Bilateral neck flexion.
Attachments of Scalenus Medius
Proximal: transverse processes of C1 and C2 and posterior tubercles of C3-C7 vertebrae.
Distal: superior surface of 1st rib, between tubercle of the rib and the groove for the subclavian artery.
Attachment of Scalenus Posterior
Proximal: posterior tubercles of transverse processes of C4, C5 and C6.
Distal: outer surface of 2nd rib behind the attachment of Serratus Anterior.
Actions of Scalenus Medius and Scalenus Posterior
Ipsilateral side flexion of the neck
Attachments of Rectus Abdominis
Proximal: two tendons from anterior aspect of pubic symphysis and pubic crest.
Distal: anterior aspect of xiphoid process and the costal cartilages of 5th, 6th and 7th ribs.
Actions of Rectus Abdominis
Flexion of the trunk.
Unilaterally it assists the obliques in ipsilateral side flexion of the trunk,
Attachments of External Oblique
Proximal: fleshy strips to outer borders of lower eight ribs and their costal cartilages. Interdigitates with Serratus Anterior above and Latissimus Dorsi below.
Distal: vertical fibres from lower two ribs attach to outer lip of anterior two thirds of iliac crest. Remainder of fibres give rise to a large aponeurosis, the fibres of which sweep across Rectus Abdominis, participating in the rectus sheath, and pass towards the midline to fuse with that of the opposite side at the linea alba.
Lower border stretches between the pubic tubercle and the ASIS and forms the inguinal ligament.
Actions of External Oblique
Contralateral rotation and ipsilateral side flexion of the thorax and shoulders when pelvis is fixed.
Ipsilateral rotation of the pelvis when the shoulders are fixed.
Draws the hip and pelvis up if the trunk if fixed (hop hitching).
Attachments of Internal Oblique
Proximal: lateral two thirds of the inguinal ligament, anterior two thirds of iliac crest and the thoracolumbar fascia.
Distal: posterior fibres attach to inferior borders of lower four ribs.
Anterior and lower fibres form an aponeurosis which interlaces with the muscle of the opposite side at the linea alba.
The part of the muscle arising from the inguinal ligament attaches by the conjoint tendon to the pubic crest and pectin pubis.
Actions of Internal Oblique
Ipsilateral rotation and side flexion if the pelvis is fixed.
Attachments of Transversus Abdominus
Proximal: inferiorly it arises from the lateral third of the inguinal ligament and anterior two thirds of the inner lip of the iliac crest. Posteriorly it arises from the thoracolumbar fascia. Superiorly it arises from the inner surface of the costal cartilages of the lower six ribs and interdigitates with the attachment of the diaphragm.
Distal: attaches to the linea alba by the aponeurotic sheet. By the conjoint tendon it attaches to the pubic crest and pectin pubis.