trunk Flashcards
- The vertebral column: gross anatomy, syndesmology and X-ray anatomy
- Function:
o Supports the weight of the Upper body
o Maintains posture and facilitates movement
o Houses and Protects the spinal cord
Intervertebral disc - Fibrocartilaginous structure
- Acts as cushion to prevent shock and stress
between two vertebrae except between the
first two cervical vertebrae and between the
sacrum and coccyx - Prevents friction
- Cervical region(C)- 7 vertebrae of the
neck - Thoracic Vertebrae(T)- 12 vertebrae
of the thorax - 3 Lumbar vertebrae (L)- 5 vertebrae of
the loin - 4 sacrum (S)- is formed from 5 fused
vertebrae - 5 coccyx (Co)- is formed from 4-5
fused rudimentary vertebrae
Ligaments between the vertebrae
>between occipital bone and 7th cervical
vertebra
・ Nuchal Lig.
> between the vertebral bodies:
・ Ant. longitudinal Lig.
・ Post. longitudinal Lig.
> between the vertebral arches:
・ Ligamenta flava (yellow)
> between the transverse processes:
・ Intertransverse Lig.
> between the spinous processes:
・ Interspinous Lig.
・ Supraspinous Lig.
Functional anatomy of the atlantooccipital and atlantoaxial joints.
Atlantoaxial joint: (divided into two parts).
● Median atlantoaxial joint:
a) Type: pivot (synovial joint).
b) Articular facets:
▪ Anterior part: facet for dens of the
atlas and anterior articular facet of
the dens.
▪ Posterior part: posterior articular
facet of the dens and transverse
ligament of atlas.
c) Ligaments:
1. Alar ligaments.
2. Apical ligament of dens.
3. Tectorial membrane.
4. Cruciate ligament of atlas: - Transverse ligament.
- Longitudinal ligament.
● Lateral atlantoaxial joint:
a) Type: plane (synovial joint).
b) Articular facets: inferior articular facet of atlas and superior articular facet of axis.
c) Ligaments: (no ligaments).
✓ Movements: We only have one significant movement which is rotation.
(Transverse plane, vertical axis).
The bones and joints of the thorax, the movements of respiration
The thorax consists of 2 bones: The sternum and the Ribs
1. Sternum:
o flat bone
o Parts:
a) Manubrium
b) body of sternum
c) xiphoid process
d) sternal angle (Louis
angle)
o Location: in the center
of the chest
2. Ribs:
o curved flat bone - 12 pairs
o True ribs (1-7): articulate directly
with the sternum o False ribs (8-10):
do not articulate directly with the
sternum
o Floating ribs (11-12): articulate with
vertebral body only, have small
costal cartilage
o Parts of a rib:
a) head of the rib - has
articular facet + crest of
the head of the rib
b) neck of the rib
c) body of a rib – has tubercle of rib (1-10), costal groove, angle of rib.
d) costal cartilage: hyaline cartilage (may ossify). From 1-10
o Curvatures of the rib:
a) Edge curvature - first rib only
b) Flat surface curvature- 2-12 ribs
c) Longitudinal twist - 2-12 ribs
Joints of the thorax:
1) costovertebral joint:
A. Joint of head of the rib (1-12):
o Type: pivot (synovial joint)
o Articular facets: articular facet
of the head of the rib &
transverse costal facet
o Ligaments:
1. Intraarticular ligament of
head of rib
2. Radiate ligament of head of
rib
B. Costotransverse joint (1-10):
o Type: pivot (synovial joint)
o Articular facets: articular facet of tubercle of rib & transverse costal facet
o Ligaments: costotransverse ligaments
2) Sternocostal joints:
o
Type: 1. 1st sternocostal joint: synarthrosis (not synovial)
2. 2nd to 7th sternocostal joints: diarthrosis (synovial)
o Articular facets: cartilages of ribs & costal notches on sternum
o Ligaments: 1. radiate sternocostal ligament -> sternal membrane
2. inter-articular sternocostal ligaments.
3) interchondral joints:
o Type: synovial joint
(diarthrosis)
o Articular facets: between 6
10 costal cartilages
o Movements: small sliding
movements
4) manubriosternal symphysis:
o Type: symphysis
o Articular facets: body of
sternum & manubrium of
sternum
5) xiphisternal joint: (angle of Louis)
o Type: synchondrosis
o Articular facets: body of sternum & xiphoid process
Ligaments: Xiphisternal ligament
6) sternoclavicular joint
The movements of Respiration
Inspiration
— Movements:
・The rib cage is elevated.
・The sternum moves to the superior-anterior direction.
・The diaphragm moves to downward.
— Participating muscles:
・Ext. intercostal muscle
・Serratus post. sup. muscle
・Levator costarum
Expiration
— Movements:
・The rib cage is depressed.
・The sternum moves to the inferior-posterior direction.
・The diaphragm moves upward.
— Participating muscles:
・Int. intercostal muscle
・Innermost intercostal muscle
・Subcostalis
・Transverses thoracis
・Serratus post. inf. Muscle
The diaphragm
separates the thoracic cavity (heart, lungs & ribs) from the abdominal cavity.
・performs an important function in respiration:
**As the diaphragm contracts, the volume of the thoracic cavity increases and air is drawn
into the lungs **
● Origin:
o costal part: lower margin of costal arch. Inner surface of 7
12 ribs
o lumbar part: right and left crura.
o Medial parts: L1-L3 vertebral bodies, 2nd + 3rd
intervertebral disks, anterior longitudinal ligament
o Lateral parts: medial and lateral arcuate ligaments
● Insertion: central tendon
● Actions:
o principal muscle of respiration
o o Helps in compressing the abdominal viscera.
● Nerve supply:
o The diaphragm is primarily innervated by the phrenic nerve which is formed from the
cervical nerves C3, C4, and C5. (A useful mnemonic to remember this is, “C-3, 4, 5
keep the diaphragm alive.”)
o central portion of the diaphragm : sends sensory afferents via the phrenic nerve
peripheral portions of the diaphragm : send sensory afferents via the intercostal
nerves
● Blood supply:
o Superior + inferior phrenic arteries from lower
thoracic aorta and upper part of abdominal aorta
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o Musculophrenic artery internal o
Pericardiacphrenic artery thoracic artery
● Apertures through the diaphragm:
1. vena caval hiatus
2. Esophageal hiatus
3. Aortic hiatus
4. Lumbar part
5. Sternal part (sternocostal triangle)
The muscles and layers of the thoracic wall. The intercostal space.
layers of the thoracic wall:
1. Skin
2. Subcutaneous tissue - the thoracoepigastric veins run In this layer
3. Pectoral fascia - encloses the pectoralis major
4. Clavipectoral fascia located under the pectoralis major spreads between the clavicle,
coracoid process, costal cartilages and pectoralis minor encloses the pectoralis minor
and subclavius
5. Thoracic fascia the superficial fascia of all ribs and Intercostal spaces
6. Intercostal space
7. Parietal fascia of thorax / endothoracic fascia- lines the inner surface of the thoracic
cavity
7. 1.Suprapleural membrane / fascia of Sibson - a thicker fascia at the pleural
cupula
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8. Parietal
pleura
The muscles of the thoracic cavity
1. External Intercostals
● There are 11 pairs of external intercostal muscles.
● They run inferoanteriorly from the rib above to the rib below,
● continuous with the external oblique of the abdomen
Attachments: Originate at the lower border of the rib, inserting into the superior
border of the rib below.
Actions: Elevates the ribs, increasing the thoracic volume.
Innervation: Intercostal nerves (T1-T11)
2. Internal Intercostals
● flat muscles lie deep to the external intercostals.
● Run inferoposteriorly from the rib above to the one below
They are continuous with the internal oblique muscle of the abdominal wall.
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● Attachments: Originates from the lateral edge of the costal groove and inserts into the
superior surface of the rib below.
● Actions: The interosseous part reduces the thoracic volume by depressing the ribcage,
and the interchondral part elevates the ribs.
● Innervation: Intercostal nerves (T1-T11).
3. Innermost Intercostals
● These muscles are the deepest of the intercostal muscles
● They are separated from the internal intercostals by the intercostal neurovascular
bundle
● found in the most lateral portion of the intercostal spaces.
● Attachments: Originates from the medial edge of the costal groove and inserts into
the superior surface of the rib below.
● Actions: The interosseous part reduces the thoracic volume by depressing the
ribcage, and the interchondral part elevates the ribs.
● Innervation: Intercostal nerves (T1-T11)
4. Transversus Thoracis
● continuous with transversus abdominis inferiorly.
● Attachments: From the posterior surface of the inferior sternum to the internal
surface of costal cartilages 2-6.
● Actions: Weakly depress the ribs.
● Innervation: Intercostal nerves (T1-T11).
5. Subcostalis
● found in the inferior portion of the thoracic wall.
● comprise of thin slips of muscle
● run from the internal surface of one rib, to second and third ribs below. The
direction of the fibres parallels that of the innermost intercostal.
● Attachments: These originate from the inferior surface of the lower ribs, near the
angle of the rib. They then attach to the superior border of the rib 2 or 3 below.
● Actions: Share the action of the internal intercostals
● Innervation: Intercostal nerves
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Intercostal spaces
1. located between adjacent ribs.
2. They contain three layers of intercostal muscles. From superficial to deep these are the
external intercostal muscles, internal intercostal muscles and the innermost intercostal
muscles.
3. The intercostal neurovascular bundle runs between the internal and innermost
intercostal muscles.
4. It passes just below the lower margin of the rib in the costal groove.
Content
1. External intercostal muscles
2. Internal Intercostal muscles
3. Intercostal neurovascular bundle
3.1. Anterior and posterior Intercostal vein
3.2 Anterior and posterior Intercostal artery
3.3. Intercostal nerve
4. Collateral Neurovascular bundle
4.1. Collateral branch of posterior Intercostal artery
4.2 Collateral branch of Intercostal nerve which runs In the Inferior and posterior
part of the intercostal space
5. Innermost Intercostal muscles
The muscles of the posterior abdominal wall and the deep muscles of the back.
Quadratus Lumborum
Origin: Iliac crest and iliolumbar ligament1
Insertion: Transverse processes of L1 – L4 and the inferior border of the 12th rib1
Innervation: Anterior rami of T12 – L4 nerves1
Action: Extension and lateral flexion of the vertebral column. It also fixes the 12th rib during inspiration, so that the contraction of diaphragm is more efficient1
Psoas major muscle
Origin: Transverse processes and vertebral bodies of T12 – L51
Insertion: Lesser trochanter of the femur1
Innervation: Anterior rami of L1 – L3 nerves1
Action: Flexion of the thigh at the hip and lateral flexion of the vertebral column1
Psoas minor muscle
Origin: Vertebral bodies of T12 and L11
Insertion: Pectineal line on the superior ramus of the pubic bone1
Innervation: Anterior rami of the L1 spinal nerve1
Action: Flexion of the vertebral column1
IlHere are the deep muscles of the back along with their origin, insertion, innervation, and action:
-
Erector Spinae
- Origin: Iliac crest, sacrum, transverse and spinous processes of vertebrae and supraspinal ligament².
- Insertion: Angles of the ribs, transverse and spinous processes of vertebrae, posterior aspect of the skull².
- Innervation: Segmentally innervated by dorsal primary rami of spinal nerves C1-S5².
- Action: Extends and laterally bends the trunk, neck, and head².
-
Iliocostalis
- Origin: Iliac crest and sacrum².
- Insertion: Angles of the ribs².
- Innervation: Dorsal primary rami of spinal nerves C4-S5².
- Action: Extends and laterally bends the trunk and neck².
-
Longissimus
- Origin: Transverse process at inferior vertebral levels².
- Insertion: Transverse process at superior vertebral levels and mastoid process².
- Innervation: Dorsal primary rami of spinal nerves C1-S1².
- Action: Extends and laterally bends the trunk, neck, and head².
-
Multifidus
- Origin: Sacrum, transverse processes of C3-L5².
- Insertion: Spinous processes 2-4 vertebral levels superior to their origin².
- Innervation: Dorsal primary rami of spinal nerves C1-L5².
- Action: Extend and laterally bend trunk and neck, rotate to opposite side².
-
Interspinales
- Origin: Upper border of spinous process².
- Insertion: Lower border of spinous process above².
- Innervation: Dorsal primary rami of spinal nerves C1-L5².
- Action: Extend trunk and neck².
-
Intertransversarii
- Origin: Upper border of transverse process².
- Insertion: Lower border of transverse process above².
- Innervation: Dorsal primary rami of spinal nerves C1-L5².
- Action: Laterally bend trunk and neck².
-
Obliquus Capitis Inferior
- Origin: Spinous process of the axis².
- Insertion: Transverse process of atlas².
- Innervation: Suboccipital nerve (DPR of C1)².
- Action: Rotates the head to the same side².
-
Obliquus Capitis Superior
- Origin: Transverse process of atlas².
- Insertion: Occipital bone above inferior nuchal line².
- Innervation: Suboccipital nerve (DPR of C1)².
- Action: Extends the head, rotates the head to the same side².
Sure, here are the remaining deep muscles of the back along with their origin, insertion, innervation, and action:
-
Rotatores
- Origin: Transverse processes of vertebrae².
- Insertion: Spinous process of the next one or two vertebrae above².
- Innervation: Dorsal primary rami of spinal nerves C1-L5².
- Action: Extend and laterally bend trunk and neck, rotate to opposite side².
-
Semispinalis
- Origin: Transverse processes of vertebrae².
- Insertion: Spinous processes of the vertebrae two to six segments above².
- Innervation: Dorsal primary rami of spinal nerves C1-L5².
- Action: Extend and rotate trunk and neck². -
Splenius Capitis
- Origin: Spinous processes of vertebrae C7-T3 and the lower half of the nuchal ligament².
- Insertion: Mastoid process and the lateral third of the superior nuchal line of the occipital bone².
- Innervation: Posterior rami of the middle and lower cervical spinal nerves².
- Action: Extend, rotate, and laterally bend the head². -
Splenius Cervicis
- Origin: Spinous processes of vertebrae T3-T6².
- Insertion: Transverse processes of vertebrae C1-C3 or C4².
- Innervation: Posterior rami of the middle and lower cervical spinal nerves².
- Action: Extend, rotate, and laterally bend the neck².
The surface projections of thoracic organs. Topography of the thoracic cavity, the
divisions of the mediastinum.
The anatomy, blood supply and lymphatic drainage of the female breast.
❖ The breasts are paired structures located on the anterior thoracic wall, in the pectoral region.
❖ In females, the breasts contain the mammary glands – an accessory gland of the female
reproductive system.
❖ The mammary glands are the key structures involved in lactation.The breast is located on the
anterior thoracic wall.
❖ It extends horizontally from the lateral border of the sternum to the mid-axillary line.
Vertically, it spans between the 2nd and 6th intercostal cartilages. It lies superficially to the
pectoralis major and serratus anterior muscles.
The breast can be considered to be composed of two regions:
● Circular body – largest and most prominent part of the breast.
● Axillary tail – smaller part, runs along the inferior lateral edge of the pectoralis major
towards the axillary fossa.
At the centre of the breast is the nipple, composed mostly of smooth muscle fibres. Surrounding
the nipple is a pigmented area of skin termed the areolae.
There are numerous sebaceous glands within the areolae – these enlarge during pregnancy,
secreting an oily substance that acts as a protective lubricant for the nipple.
Mammary Glands
❖ The mammary glands are modified sweat glands. They consist of a series of ducts and
secretory lobules (15-20).
❖ Each lobule consists of many alveoli drained by a single lactiferous duct. These ducts
converge at the nipple like spokes of a wheel.
Connective Tissue Stroma
The connective tissue stroma is a supporting structure which surrounds the mammary glands. It
has a fibrous and a fatty component.
The fibrous stroma condenses to form suspensory ligaments (of Cooper). These ligaments have
two main functions:
● Attach and secure the breast to the dermis and underlying pectoral fascia.
● Separate the secretory lobules of the breast.
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Pectoral Fascia
The base of the breast lies on the pectoral fascia – a flat sheet of connective tissue associated
with the pectoralis major muscle. It acts as an attachment point for the suspensory ligaments.
There is a layer of loose connective tissue between the breast and pectoral fascia – known as the retromammary space. This is a potential space, often used in reconstructive plastic surgery.
Blood supply
Arterial supply to the medial aspect of the breast is via the internal thoracic artery, a branch of
the subclavian artery.
The lateral part of the breast receives blood from four vessels:
● Lateral thoracic and thoracoacromial branches – originate from the axillary artery.
● Lateral mammary branches – originate from the posterior intercostal arteries (derived from
the aorta). They supply the lateral aspect of the breast in the 2nd 3rd and 4thintercostal
spaces.
● Mammary branch – originates from the anterior intercostal artery.
The veins of the breast correspond with the arteries, draining into the axillary and internal
thoracic veins.
The lymphatic drainage of the breast is of great clinical importance due to its role in the
metastasis of breast cancer cells.
There are three groups of lymph nodes that receive lymph from breast tissue – the axillary
nodes (75%), parasternal nodes (20%) and posterior intercostal nodes (5%).
The skin of the breast also receives lymphatic drainage:
● Skin – drains to the axillary, inferior deep cervical and infraclavicular nodes.
● Nipple and areola – drains to the subareolar lymphatic plexus.
The breast is innervated by the anterior and lateral cutaneous branches of the 4th to 6th
intercostal nerves.
The definition and structures of the superior mediastinum. Topography and developmental stages
of the thymus.
The superior mediastinum is the upper part of the mediastinum, which is the central compartment of the thoracic cavity located between the two pleural sacs12. It extends upwards, terminating at the superior thoracic aperture, and downwards, terminating at the sternal angle1.
The superior mediastinum is bordered by1:
Superior: Thoracic inlet
Inferior: Continuous with the inferior mediastinum at the level of the sternal angle
Anterior: Manubrium of the sternum
Posterior: Vertebral bodies of T1-4
Lateral: Pleurae of the lungs
The superior mediastinum contains several important structures134:
Esophagus: The part of the alimentary canal that connects the throat to the stomach
Trachea: The windpipe, a tube that connects the pharynx and larynx to the lungs
Thymus: A lymphoid organ that produces T-cells
Vagus Nerve (CN X): The tenth cranial nerve, which interfaces with the parasympathetic control of the heart, lungs, and digestive tract
Phrenic Nerves: Nerves that originate in the neck (C3-C5) and pass down between the lung and heart to reach the diaphragm
Superior Vena Cava: A large vein carrying deoxygenated blood into the heart
Brachiocephalic Veins: Veins formed by the union of the internal jugular and subclavian veins
Aortic Arch and Its Branches: The part of the aorta that bends between the ascending and descending aorta, giving rise to the brachiocephalic trunk, left common carotid artery, and left subclavian artery
Thoracic Duct: The largest lymphatic vessel in the body, which drains a major portion of the body’s lymph into the bloodstream
Thymus
● The thymus gland is the most anterior structure within the superior mediastinum.
● It sits flush against the posterior surface of the sternum and extends into the anterior
mediastinum and can often reach into the neck.
● The thymus is a lymphoeplthellal organ located in the ventral part of the superior
mediastinum just behind the sternum.
● It contains T-lymphocytes undergoing maturation. The T-lymphocytes are selected in the
thymus to recognise self from non-self, meaning they are programmed to recognise and
attack foreign antigens that may be a potential threat to the organism.
● The thymus is the largest and most active during the neonatal period.
● During the teenage years it begins to atrophy and involute. After the age of around fifty,
the thymus is almost completely replaced by an adipose tissue. However, residual
thymus tissue may persist throughout the rest of life.
Development —
● The thymus appears in the form of two flask-shaped endoterm diverticula, which arise,
one on either side, from the third branchial pouch and extend lateralward and backward
into the surrounding mesoderm in front of the ventral aortæ.
● they meet and become joined to one another by connective tissue, but there is never
any fusion of the thymus tissue proper.
● The pharyngeal opening of each diverticulum is soon obliterated, but the neck of the
flask persists for some time as a cellular cord. By further proliferation of the cells lining
the flask, buds of cells are formed, which become surrounded and isolated by the
invading mesoderm. In the latter, numerous lymphoid cells make their appearance, and
are agregated to form lymphoid follicles. These lymphoid cells are probably derivatives
of the entodermal cells which lined the original diverticula and their subdivisions.
● Additional portions of thymus tissue are sometimes developed from the fourth
branchial pouches. Thymus continues to grow until the time of puberty and then begins
to atrophy.
Upper airways: functional anatomy of the nasal cavity and paranasal
sinuses
● The nasal cavity is open through the nostrils to the external environment.
● Dorsally, it communicates with the nasopharynx through the posterior nasal apertures.
● The anterior apertures of the nasal cavities are the nares.
● The posterior apertures are the choanae, which open into the nasopharynx.
● It Is divided sagittally by the nasal septum, which is composed of cartilage ventrally and
bone dorsally.
● The floor of the nasal cavity is formed by the palate.
● The three conchae (inferior, medial and superior) protrude from the lateral wall and
divide the cavity into four groove-like air passages, the inferior, middle, superior and
common meatuses, which communicate with the paranasal sinuses and the
nasolacrimal duct.
● The roof is formed by the base of the anterior cranial fossa and is involved in olfaction.
● The nasal cavity serves to heat and humidity inspired air, and mechanically blocks
particles from entering.
Nasal Conchae
❖ Projecting out of the lateral walls of the nasal cavity are curved shelves of bone. They are
called conchae (or turbinates). The are three conchae – inferior, middle and superior.
❖ They project into the nasal cavity, creating four pathways for the air to flow. These
pathways are called meatuses:
● Inferior meatus: Lies between the inferior concha and floor of the nasal cavity.
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● Middle meatus: Lies between the inferior and middle concha.
● Superior meatus: Lies between the middle and superior concha.
● Spheno-ethmoidal recess: Lies superiorly and posteriorly to the superior concha.
The function of the conchae is to increase the surface area of the nasal cavity – this
increases the amount of inspired air that can come into contact with the cavity
walls. They also disrupt the fast, laminar flow of the air, making it slow and turbulent.
The air spends longer in the nasal cavity, so that it can be humidified.
❖ The paranasal sinuses are air-filled extensions of the respiratory part of the nasal cavity.
❖ There are four paired sinuses, named according to the bone in which they are located;
maxillary, frontal, sphenoid and ethmoid.
❖ The function of the sinuses is not clear. It is thought that they may
contribute to the humidifying of the inspired air. They also reduce the
weight of the skull.
❖ Sinuses are formed in childhood by the nasal cavity eroding into surrounding
bone. As they are outgrowths of the nasal cavity, they all drain back into it –
openings to the paranasal sinuses are found on the roof and lateral walls of the
nasal cavity. The inner surface is lined by a respiratory mucosa.
The cartilages, ligaments and cavity of the larynx. The anatomy of the hyoid bone.
Laryngoscopic image.
