Back and Pectoral Region Flashcards
common causes of back and neck pain
*sprain and strain of the back or neck;
*pain arising from the discs of the spine themselves,
called “discogenic pain”;
*pain that results when bulging discs compress nerves,
called “radicular pain”;
*pain from arthritis (any type) of the facet joints – the
joints that hold the spine in alignment (“facet joint
syndrome”)
*pain from bony compression of the nerves of the spine, which is called spinal stenosis.
What is the back?
Runs from the neck to the pelvis. It is supported by the vertebral column and the ribs posteriorly. The
scapula is NOT part of the back –it is part of the appendicular skeleton. It has neural elements (spinal
cord and associated spinal roots and rami). Also has muscular support it’s very intricate.
Thoracolumbar Fascia
–> continuous with the superficial layer of the investing cervical fascia
–> separates two major groups of muscles – muscles in the back are either EXTRINSIC or INTRINSIC and this
fascia separate them and attaches to the spinous processes of both the thoracic vertebrae and to the angles of the ribs.
–> Some muscles actually originate from that thoracolumbar fascia and play an important role.
–>Comes down and attaches to the iliac crest and muscles in the lumbar region.
–> there’s an anterior layer (visible only when looking through the abdomen), a middle layer, and a posterior layer. which isolate the INTRINSIC or DEEP BACK MUSCLES which are the ERECTOR SPINAE group of
muscles - which help hold your spine erect
from the EXTRINSIC MUSCLES
Extrinsic vs. Intrinsic Back Muscles
• Extrinsic Muscles
– have a different embryological origin than the intrinsic muscles ( Hypaxial portion of Myotome).
They originate outside of the back and they migrate in.
– Extrinsic muscles originate outside of the back
– Extrinsic muscle groups
• superficial (lattisimus, the rhomboids)
• intermediate
– Extrinsic are innervated by VENTRAL PRIMARY RAMI
• Intrinsic Muscles
– Originate within the back (Epaxial portion of
Myotome)
Intrinsic are innervated by DORSAL PRIMARY RAMI
– Intrinsic muscle group
• deep (with 3 subdivisions of deep)
Extrinsic Muscles
Extrinsic move upper limbs and ribs and are innervated by ventral rami or CN-XI
A) Superficial (appendicular group)
1. Trapezius 2. Latissimus Dorsi 3. Rhomboids (major and minor) 4. Levator Scapulae
B) Intermediate (respiratory group)
1. Superior posterior serratus 2. Inferior posterior serratus
Intrinsic Muscles
Intrinsic move vertebral column; maintain posture; aka deep muscles of the back
innervation from dorsal primary rami and covered by thoracolumbar fascia
- Extensors and rotators of head and neck (spinotransversales)
- – splenius capitis & splenius cervicis
- Extensors and rotators of vertebral column
- – erector spinae & transversospinales
- Short segmental muscles
- – interspinales & intertransversarii
Ausculatory Triangle
Boundaries
Lower border of trapezius
Latissimus dorsi
Medial margin of scapula
Best location to hear sounds of respiration with stethoscope because of lack of intervening muscle
Also called triangle of auscultation
Back VAN
The neurovascular bundle runs between innermost and internal intercostal muscles in the costal groove of ribs
Intercostal & Lumbar Arteries
Suboccipital Muscles
located within the suboccipital compartment of the neck; deep to the sternocleidomastoid, trapezius, splenius and semispinalis muscles. They collectively act to extend and rotate the head.
1 Rectus Capitis Posterior Major
2 Rectus Capitis Posterior Minor
3 Obliquus Capitis Inferior
4 Obliquus Capitis Superior
5 Suboccipital Triangle
Suboccipital Triangle
The suboccipital triangle is an area bordered by three of the suboccipital muscles.
It contains the vertebral artery (can be identified during surgery), suboccipital venous plexus and dorsal ramus of C1
Its borders are as follows:
Superomedial: Rectus capitus posterior major
Superolateral: Obliquus capitus superior
Inferior: Obliquus capitus inferior
Floor: Posterior atlanto-occiptal membrane and posterior arch of the C1 vertebrae (atlas)
Roof: Semispinalis capitus
Pectoral Region
External to the anterior thoracic wall
Anchors the upper limb to the trunk.
Pectoral Region consists of:
• a superficial compartment containing skin, superficial fascia, and breasts; and
• a deep compartment containing muscles and associated structures.
Nerves, vessels, and lymphatics in the superficial compartment emerge from the thoracic wall, the axilla, and the neck
Breast Landmarks
base usually extends from rib 2 to rib 6
nipple at 4th intercostal space in males and immature females
ducts of the tubuloalveolar milk glands open at nipple
areola is pigmented area surrounding nipple
Breast Ducts and Glands
Glands are modified sweat glands
Ducts and Secretory Units Embedded in Adipose Tissue
Secretory Units Proliferate When Needed
Tubuloalveolar Secretory Units Synthesize Milk When Breast is Active
Ducts Bring Milk to Surface
Ligaments of the Breast
Cooper’s Ligaments (Suspensory Ligaments)
ligaments are formed from the connective tissue stroma which surround the ducts and lobules of the mammary gland – in certain areas the connective tissue condenses forming ligaments which support the breast, extending from the dermis of the overlying skin to the deep fascia. These suspensory ligaments support the breast on the chest wall and connect posteriorly with the anterior wall of the pectoralis major muscle
normally suspend the breast tissue
breast cancer may infiltrate & displace ligaments from normal position
results in dimpling of overlying skin
sometimes results in nipple eversion
Arteries of the Breast
Branches of Internal Thoracic a. (branch of subclavian)
Branches from Pectoral br. of Thoracoacromial a. ( first branch of the second part of the axillary artery at the axilla which is a continuation of the subclavian artery as it passes under the midpoint of the clavicle on the outer edge of the first rib)
Branches from Lateral Thoracic a. (branch of second part of axillary which runs laterally along the lower border of pectoralis minor to supply)
Branches from intercostal aa. posteriorly
Breasts are highly vascularized because they make proteins. They have a huge metabolic demand thus need a large arterial supply to aid in the production of milk
Drainage of Veins of the Breast
To axillary veins
To internal thoracic veins
To intercostal veins
Breast Lymphatics
75% of lymph drains laterally & superiorly to axillary nodes
Most of the other 25% of the lymph drains into parasternal nodes
This is important for understanding breast cancer as metasis makes lymphatic drainage in the breast very difficult.
It also may actually be able to cross over the parasternal nodes that go onto the other side and deep!
(early detection is key because parasternal metasis is very difficult to access/remove
Innervation of the Breast
Intercostal nerves 2-6, (anterior and lateral cutaneous branches)
Nipple by 4th intercostal nerve
Pectoral Girdle
Incomplete bony ring
Attaches appendicular (clavicle) to axial skeleton (sternal manubrium)
Clavicle
Scapula
Also called shoulder girdle or thoracic girdle
Movements of the Scapula
Protraction Retraction Abduction Adduction Flexion Extension (can touch your scapula)
Joints of Pectoral Girdle
i) Sternoclavicular joint: where the clavicle meets the sternum; The upper limb and pectoral girdle are connected to the trunk (axial skeleton) only through the sterno-clavicular joint. (real attachment of the whole thing)
ii) Acromioclavicular joint: the scapula is connected to the clavicle
iii) Glenohumeral joint: where the scapula is connected to the humerus bone; ball and socket joint which allows for mobility
Scapula does not make any anatomical joint with axial skeleton rather it is connected to the vertebral column and thorax only by the muscles. This connection of scapula with the thorax is sometimes referred as conceptual “SCAPULOTHORACIC JOINT;” slides back and forth across the back
Thus the extremely mobile pectoral girdle is supported and stabilized by the muscles that are attached to the ribs, sternum and vertebrae.
Muscles and Fascia of the Pectoral Region
Pectoralis Major
Pectoralis Minor
Subclavius
Serratus Anterior*
*not considered pectoral because it does not originate from the anterior thoracic wall and insert into the upper limb—instead it originates from the ribs and inserts into the scapula
Pectoral and Clavipectoral Fascia
Both are sheets of fibrous CT
Pectoral fascia thin, covers pectoralis major, attaches to sternum, clavicle, forms floor of axilla
Clavipectoral fascia is strong, fills gap between pectoralis minor and subclavius, covers axillary vessels and nerves, splits around subclavius and attaches posterior and anterior to the groove for the subclavius on the clavicle
The Clavipectoral (Deltopectoral) Triangle
can be palpated and can be used by an examiner to locate several structures.
ex) where cephalic vein drops and brings blood return
Between the clavicle, the deltoid, and pectoralis major.
