PAS 407 Axilla (armpit) UPDATED ACTUAL Questions and CORRECT Answers
- bony boundary formed by clavicle, 1st rib, and scapula
- location of the apex of the pyramid
- passage for structures passing between neck and axilla
Superior (apex) boundary of axilla
continuous with upper arm and is in part reinforced by the
axillary nerve
Base boundary of axilla
wall formed by the pectoral (minor and major) region of
the shoulder
border ends inferiorly at the anterior axillary fold
Anterior boundary of axilla - formed by the lateral border of pectoralis major muscle
- wall formed by the body of the scapula, associated
scapulohumeral muscles (subscapularis muscles), and
latissimus dorsi muscle
Posterior boundary of axilla
- border ends inferiorly with posterior axillary fold
- composed of both latissimus dorsi and teres major
muscles
, formed by lateral border of rib cage and overlying mus-
culature (serratus anterior)
Medial boundary of axilla
Small boundary on proximal humerus between the inser-
tions of pectoralis major, latissimus dorsi
image: lateral boundary would be the dent on the
humerus head (btw latissimus dorsi and pec muscle)
Lateral boundary of axilla
origin: ribs through 1 to 8
- named for serrated appearance of muscle origin
most superficial portion of medial wall of axilla
origin of serratus anterior muscle
insertion of serratus anterior muscle
, medial border of scapula
[note when lateral border of scapula is reflected poste-
riorly, medial border of scapula define the bottom of a
V formed by serratus anterior anteriorly and subscapu-
laris posteriorly (wedge-shaped btw posterior and medial
wall)]
contracts to protract the scapula (pull arm forward)
- important muscle in quadrupeds to elevate thorax while
walking
Notes:
slide scapula anterolaterally along wall of thoracic =
scapular protraction...this serve to max project arm ante-
riorly when reaching forward
action of serratus anterior - bc of radiating pattern of muscle fibers, selective con-
traction of superior/inferior portions of muscle can cause
upward/downward rotation of scapula respectively
another role of scapula is to work synergy with trapezius to
co-contract, pulling medial border of scapula flat against
posterior thoracic wall - important to quadrupeds
- assist in keeping scapula flat against thoracic wall, pre-
vent drooping of thoracic wall when standing or walking
long thoracic nerve
innervation of serratus anterior
- lateral thoracic artery
when can long thoracic nerve be injured?
- bony boundary formed by clavicle, 1st rib, and scapula
- location of the apex of the pyramid
- passage for structures passing between neck and axilla
Superior (apex) boundary of axilla
continuous with upper arm and is in part reinforced by the
axillary nerve
Base boundary of axilla
wall formed by the pectoral (minor and major) region of
the shoulder
border ends inferiorly at the anterior axillary fold
Anterior boundary of axilla - formed by the lateral border of pectoralis major muscle
- wall formed by the body of the scapula, associated
scapulohumeral muscles (subscapularis muscles), and
latissimus dorsi muscle
Posterior boundary of axilla
- border ends inferiorly with posterior axillary fold
- composed of both latissimus dorsi and teres major
muscles
, formed by lateral border of rib cage and overlying mus-
culature (serratus anterior)
Medial boundary of axilla
Small boundary on proximal humerus between the inser-
tions of pectoralis major, latissimus dorsi
image: lateral boundary would be the dent on the
humerus head (btw latissimus dorsi and pec muscle)
Lateral boundary of axilla
origin: ribs through 1 to 8
- named for serrated appearance of muscle origin
most superficial portion of medial wall of axilla
origin of serratus anterior muscle
insertion of serratus anterior muscle
, medial border of scapula
[note when lateral border of scapula is reflected poste-
riorly, medial border of scapula define the bottom of a
V formed by serratus anterior anteriorly and subscapu-
laris posteriorly (wedge-shaped btw posterior and medial
wall)]
contracts to protract the scapula (pull arm forward)
- important muscle in quadrupeds to elevate thorax while
walking
Notes:
slide scapula anterolaterally along wall of thoracic =
scapular protraction...this serve to max project arm ante-
riorly when reaching forward
action of serratus anterior - bc of radiating pattern of muscle fibers, selective con-
traction of superior/inferior portions of muscle can cause
upward/downward rotation of scapula respectively
another role of scapula is to work synergy with trapezius to
co-contract, pulling medial border of scapula flat against
posterior thoracic wall - important to quadrupeds
- assist in keeping scapula flat against thoracic wall, pre-
vent drooping of thoracic wall when standing or walking
long thoracic nerve
innervation of serratus anterior
- lateral thoracic artery
when can long thoracic nerve be injured?
