Triangles of the neck


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  • upper part of the common carotid artery, which bifurcates opposite the upper border of the thyroid cartilage into the external and internal carotid The external and internal carotids lie side by side, the external being the more anterior of the two . The following branches of the external carotid are also met with in this space: the superior thyroid, running forward and downward; the lingual, directly forward; the external maxillary, forward and upward; the occipital, backward; and the ascending pharyngeal, directly upward on the medial side of the internal carotid. The veins met with are: the internal jugular, which lies on the lateral side of the common and internal carotid arteries; and veins corresponding to the above-mentioned branches of the external carotid—viz., the superior thyroid, the lingual, common facial, ascending pharyngeal, and sometimes the occipital—all of which end in the internal jugular. The nerves in this space are the following. In front of the sheath of the common carotid is the ramus descendens hypoglossi. The hypoglossal nerve crosses both the internal and external carotids above, curving around the origin of the occipital artery. Within the sheath, between the artery and vein, and behind both, is the vagus nerve; behind the sheath, the sympathetic trunk. On the lateral side of the vessels, the accessory nerve runs for a short distance before it pierces the Sternocleidomastoideus; and on the medial side of the external carotid, just below the hyoid bone, may be seen the internal branch of the superior laryngeal nerve; and, still more inferiorly, the external branch of the same nerve. The upper portion of the larynx and lower portion of the pharynx are also found in the front part of this space.
  • Digastric Triangle corresponds to the region of the neck immediately beneath the body of the mandible. It is bounded, above, by the lower border of the body of the mandible, and a line drawn from its angle to the mastoid process; below, by the posterior belly of the Digastricus and the Stylohyoideus; in front, by the anterior belly of the Digastricus. It is covered by the integument, superficial fascia, Platysma, and deep fascia, ramifying in which are branches of the facial nerve and ascending filaments of the cutaneous cervical nerve. Its floor is formed by the Mylohyoideus, Hyoglossus, and Constrictor pharyngis superior. It is divided into an anterior and a posterior part by the stylomandibular ligament. The anterior part contains the submaxillary gland, superficial to which is the anterior facial vein, while imbedded in the gland is the external maxillary artery and its glandular branches; beneath the gland, on the surface of the Mylohyoideus, are the submental artery and the mylohyoid artery and nerve. The posterior part of this triangle contains the external carotid artery, ascending deeply in the substance of the parotid gland; this vessel lies here in front of, and superficial to, the internal carotid, being crossed by the facial nerve, and gives off in its course the posterior auricular, superficial temporal, and internal maxillary branches: more deeply are the internal carotid, the internal jugular vein, and thevagus nerve, separated from the external carotid by the Styloglossus and Stylopharyngeus, and the glossopharyngeal nerve.
  • The Occipital Triangle, the larger division of the posterior triangle, is bounded, in front, by the Sternocleidomastoideus; behind, by the Trapezius; below, by the Omohyoideus. Its floor is formed from above downward by the Splenius capitis, Levator scapulæ, and the Scaleni medius and posterior. It is covered by the skin, the superficial and deep fasciæ, and by the Platysma below. The accessory nerve is directed obliquely across the space from the Sternocleidomastoideus, which it pierces, to the under surface of the Trapezius; below, the supraclavicular nerves and the transverse cervical vessels and the upper part of the brachial plexus cross the space. A chain of lymph glands is also found running along the posterior border of the Sternocleidomastoideus, from the mastoid process to the root of the neck.
  • The size of the subclavian triangle varies with the extent of attachment of the clavicular portions of the Sternocleidomastoideus and Trapezius, and also with the height at which the Omohyoideus crosses the neck. Its height also varies according to the position of the arm, being diminished by raising the limb, on account of the ascent of the clavicle, and increased by drawing the arm downward, when that bone is depressed. This space is covered by the integument, the superficial and deep fasciæ and the Platysma, and crossed by the supraclavicular nerves. Just above the level of the clavicle, the third portion of the subclavian artery curves lateralward and downward from the lateral margin of the Scalenus anterior, across the first rib, to the axilla, and this is the situation most commonly chosen for ligaturing the vessel. Sometimes this vessel rises as high as 4 cm. above the clavicle; occasionally, it passes in front of the Scalenus anterior, or pierces the fibers of that muscle. The subclavian vein lies behind the clavicle, and is not usually seen in this space; but in some cases it rises as high as the artery, and has even been seen to pass with that vessel behind the Scalenus anterior. The brachial plexus of nerves lies above the artery, and in close contact with it. Passing transversely behind the clavicle are the transverse scapular vessels; and traversing its upper angle in the same direction, the transverse cervical artery and vein. The external jugular vein runs vertically downward behind the posterior border of the Sternocleidomastoideus, to terminate in the subclavian vein; it receives the transverse cervical and transverse scapular veins, which form a plexus in front of the artery, and occasionally a small vein which crosses the clavicle from the cephalic. The small nerve to the Subclavius also crosses this triangle about its middle, and some lymph glands are usually found in the space.
  • Triangles of the neck

    1. 1. Triangles ofTriangles of the Neckthe Neck By: Aljeirou D. Alcachupas
    2. 2. Muscles of the NeckMuscles of the Neck
    3. 3. Anterior TriangleAnterior Triangle BoundariesBoundaries:: front,front, by the middle line of the neckby the middle line of the neck behind,behind, by the anterior margin of the Sternocleidomastoid;by the anterior margin of the Sternocleidomastoid; base,base, directed upward, formed by the lower border of the body of thedirected upward, formed by the lower border of the body of the mandiblemandible apexapex is below, at the below, at the sternum.
    4. 4.  This space is subdividedThis space is subdivided into four smaller trianglesinto four smaller triangles by the Digastricus above,by the Digastricus above, and the superior belly of theand the superior belly of the Omohyoideus below. TheseOmohyoideus below. These smaller triangles are namedsmaller triangles are named thethe carotid,carotid, thethe submandibular,submandibular, thethe submental,submental, and theand the muscular.muscular.
    5. 5.  Muscular TriangleMuscular Triangle Boundaries:Boundaries:  Front,Front, by the median line of theby the median line of the neck from the hyoid bone to theneck from the hyoid bone to the sternum;sternum;  Behind,Behind, by the anterior margin ofby the anterior margin of the Sternocleidomastoid;the Sternocleidomastoid;  AboveAbove, by the superior belly of the, by the superior belly of the Omohyoid. It is covered by theOmohyoid. It is covered by the integument, superficial fascia,integument, superficial fascia, Platysma, and deep fasciaPlatysma, and deep fascia
    6. 6.  The muscles forming and withinThe muscles forming and within the triangle are seen in imagethe triangle are seen in image labeled:labeled:  superficial layersuperficial layer  sternohyoid (sh)sternohyoid (sh)  superior belly of omohyoidsuperior belly of omohyoid (oh)(oh)  deep layerdeep layer  thyroid (th)thyroid (th)  sternothyroid (st)sternothyroid (st)
    7. 7.  Contents: common carotid artery, internalContents: common carotid artery, internal jugular vein and vagus nerve, inferior thyroidjugular vein and vagus nerve, inferior thyroid artery, the recurrent nerve, and the sympatheticartery, the recurrent nerve, and the sympathetic trunk , esophagus, the trachea, the thyroid gland,trunk , esophagus, the trachea, the thyroid gland, and the lower part of the larynxand the lower part of the larynx
    8. 8. Thyroid gland andThyroid gland and its arterial supplyits arterial supply  When the strap musclesWhen the strap muscles are reflected, you can seeare reflected, you can see the thyroid gland (tg)the thyroid gland (tg) with its arteries (superiorwith its arteries (superior thyroid artery from thethyroid artery from the external carotid (sta) andexternal carotid (sta) and the inferior thyroid arterythe inferior thyroid artery from the thyrohyoidfrom the thyrohyoid trunk from thetrunk from the subclavian (ita).subclavian (ita).
    9. 9.  If the thyroid gland isIf the thyroid gland is reflected laterally, thereflected laterally, the structures making up thestructures making up the larynx and trachea are seen:larynx and trachea are seen:  thyrohyoid membrane (thm)thyrohyoid membrane (thm)  thyroid cartilage (Adam'sthyroid cartilage (Adam's apple)(tc)apple)(tc)  cricothyroid membrane andcricothyroid membrane and ligament (ctm)ligament (ctm)  cricoid cartilage (cc)cricoid cartilage (cc)  tracheal rings (tr)tracheal rings (tr) Cartilages and membranes
    10. 10. Anterior View of Thyroid GlandAnterior View of Thyroid Gland  The thyroid gland is hiddenThe thyroid gland is hidden under the sternohyoid andunder the sternohyoid and sternothyroid muscles andsternothyroid muscles and consists of two lobes and anconsists of two lobes and an isthmus.isthmus.  An occasional pyramidal lobeAn occasional pyramidal lobe extends upward near the midextends upward near the mid line.line.  The inferior thyroid artery isThe inferior thyroid artery is closely associated with theclosely associated with the recurrent laryngeal nerverecurrent laryngeal nerve (rln).(rln).
    11. 11. Boundaries:Boundaries:  Above,Above, by the posteriorby the posterior belly of digastricbelly of digastric muscle and stylohyoidmuscle and stylohyoid  Below,Below, by the superiorby the superior belly of the omohyoidbelly of the omohyoid muscle (so)muscle (so)  BehindBehind, anterior border, anterior border of sternomastoidof sternomastoid musclemuscle Carotid Triangle
    12. 12.  Roof of the carotid:Roof of the carotid: The first layer, under theThe first layer, under the skin and superficial fasciaskin and superficial fascia includes the platysma,includes the platysma, which forms the roof ofwhich forms the roof of the carotid triangle. Notethe carotid triangle. Note the location of thethe location of the carotid triangle in purple.carotid triangle in purple.
    13. 13.  Floor of the carotid:Floor of the carotid: The floor is the the deepestThe floor is the the deepest aspect of the carotid triangle.aspect of the carotid triangle.  The muscles, at this level, areThe muscles, at this level, are the middle and lowerthe middle and lower pharyngeal constrictors (mpcpharyngeal constrictors (mpc and ipc).and ipc).  The structures seen passingThe structures seen passing through this level are:through this level are:  superior laryngeal nerve, asuperior laryngeal nerve, a branch of the vagus its 2branch of the vagus its 2 terminal branchesterminal branches  internal laryngeal (ilb--sensoryinternal laryngeal (ilb--sensory to upper part of the larynx)to upper part of the larynx)  external laryngeal (elb--motorexternal laryngeal (elb--motor to the cricoid muscle)to the cricoid muscle)
    14. 14.  Contents: upper part of the common carotidContents: upper part of the common carotid artery, internal jugular vein, hypoglossal nerve,artery, internal jugular vein, hypoglossal nerve, vagus nerve, accessory nerve, internal branch ofvagus nerve, accessory nerve, internal branch of the superior laryngeal nerve, external branch ofthe superior laryngeal nerve, external branch of the superior laryngeal nervethe superior laryngeal nerve
    15. 15.  Veins within the CarotidVeins within the Carotid With the roof removed, here are theWith the roof removed, here are the boundaries of the carotid triangleboundaries of the carotid triangle and the superficial veins related toand the superficial veins related to it:it:  common facial vein (cf) (common facial vein (cf) (within carotidwithin carotid triangle)triangle)  Other structures near by:Other structures near by:  retromandibular vein (retromandibular vein (rmrm))  posterior auricular vein (posterior auricular vein (pavpav))  facial vein (facial vein (fvfv))  external jugular vein (external jugular vein (ejej))  anterior jugular vein (anterior jugular vein (ajaj))
    16. 16. Nerves within the Carotid TriangleNerves within the Carotid Triangle
    17. 17.  The nerves that enter theThe nerves that enter the carotid triangle and thatcarotid triangle and that lie superficial to thelie superficial to the internal jugular vein,internal jugular vein, internal and externalinternal and external carotid arteries are:carotid arteries are:  hypoglossal (XII)hypoglossal (XII)  C1 root of ansa cervicalisC1 root of ansa cervicalis (C1)(C1)  C1 fibers running withC1 fibers running with hypoglossal nerve (nervehypoglossal nerve (nerve to thyrohyoid muscleto thyrohyoid muscle (nth)(nth)  C2-C3 root of ansaC2-C3 root of ansa cervicaliscervicalis  ansa cervicalis (ac)ansa cervicalis (ac)
    18. 18. Reflection of sternomastoid andReflection of sternomastoid and removal of common facial veinremoval of common facial vein  ccacca-common carotid artery-common carotid artery ecaeca-external carotid artery-external carotid artery  stasta-supterior thyroid artery-supterior thyroid artery  oaoa-occipital artery-occipital artery  lala-lingual artery-lingual artery  fafa-facial artery-facial artery  icaica-internal carotid artery-internal carotid artery
    19. 19. Arteries in the Carotid TriangleArteries in the Carotid Triangle
    20. 20.  corresponds to the region of thecorresponds to the region of the neck immediately beneath theneck immediately beneath the body of the mandible.body of the mandible. Boundaries:Boundaries:  Above,Above, by the lower border of theby the lower border of the body of the mandible and thebody of the mandible and the mastoid processmastoid process  Below,Below, by the posterior belly ofby the posterior belly of the Digastric and the Stylohyoid;the Digastric and the Stylohyoid;  Front,Front, by the anterior belly of theby the anterior belly of the Digastric.Digastric.  Floor,Floor, coverd by mylohiodeuscoverd by mylohiodeus Submandibular Triangle
    21. 21.  The superficial (roof)The superficial (roof) structures of thestructures of the submandibular regionsubmandibular region are:are:     platysmaplatysma  facial vein (fv)facial vein (fv)  cervical branch of facialcervical branch of facial nerve (cbf)nerve (cbf)
    22. 22.  Contents:Contents: Anterior part:Anterior part: submaxillary gland,submaxillary gland, anterior facial vein,anterior facial vein, external maxillaryexternal maxillary artery, submentalartery, submental artery, mylohyoidartery, mylohyoid artery and nerve,artery and nerve, external carotidexternal carotid artery, internalartery, internal carotid artery, facialcarotid artery, facial nervenerve
    23. 23.  Removal of the superficialRemoval of the superficial structures displays thestructures displays the submandibular salivary glandsubmandibular salivary gland itself.itself.
    24. 24.  contents of thecontents of the submandibular triangle aresubmandibular triangle are structures passing through:structures passing through:  facial artery (fa)facial artery (fa)  lingual nerve andlingual nerve and submandibular ganglionsubmandibular ganglion (ln)(ln)  submandibular duct (smd)submandibular duct (smd)  lingual artery (la)lingual artery (la)  hypoglossal nerve (XII)hypoglossal nerve (XII)  the lingual nerve andthe lingual nerve and submandibular duct passsubmandibular duct pass through a gap between thethrough a gap between the hypoglossal (hg) andhypoglossal (hg) and mylohyoid (mh) musclesmylohyoid (mh) muscles  the lingual artery passes deepthe lingual artery passes deep to the hyoglossus the hyoglossus muscle.
    25. 25. Submental TriangleSubmental Triangle BoundariesBoundaries BBehind,ehind, by the anterior bellyby the anterior belly of the Digastricusof the Digastricus Front,Front, by the middle line ofby the middle line of the neck between the mandiblethe neck between the mandible and the hyoid boneand the hyoid bone Below,Below, by the body of theby the body of the hyoid bone;hyoid bone; FloorFloor is formed by theis formed by the Mylohyoideus which aids inMylohyoideus which aids in swallowing and in depressingswallowing and in depressing the mandible.the mandible.  StructuresStructures  submental lymph node(s) (ln) -submental lymph node(s) (ln) - drain the floor of the mouth.drain the floor of the mouth.  some small veins; the lattersome small veins; the latter unite to form the anteriorunite to form the anterior jugular vein.jugular vein.
    26. 26. Posterior TrianglePosterior Triangle BoundariesBoundaries:: Front,Front, by the Sternocleidomastoid;by the Sternocleidomastoid; Behind,Behind, by the anterior margin of the Trapezius;by the anterior margin of the Trapezius; BaseBase, by the middle third of the clavicle, by the middle third of the clavicle Apex,Apex, by the occipital bone. The space is crossed, above the clavicle, byby the occipital bone. The space is crossed, above the clavicle, by the inferior belly of the Omohyoid, which divides it into, anthe inferior belly of the Omohyoid, which divides it into, an upperupper oror occipital,occipital, and aand a lowerlower oror supraclavicular.supraclavicular.
    27. 27. Occipital TriangleOccipital Triangle Boundaries:Boundaries: Front,Front, by theby the SternocleidomastoidSternocleidomastoid Behind,Behind, by the Trapeziusby the Trapezius Below,Below, by the the Omohyoid. FloorFloor is formed from aboveis formed from above downward by the Spleniusdownward by the Splenius capitis, Levator scapulæ, andcapitis, Levator scapulæ, and the Scaleni medius andthe Scaleni medius and posterior.posterior.
    28. 28.  It is covered byIt is covered by the skin, thethe skin, the superficial andsuperficial and deep fasciæ, anddeep fasciæ, and by the Platysmaby the Platysma below.below.
    29. 29.  Contents: accessoryContents: accessory nerve, supraclavicularnerve, supraclavicular nerves and thenerves and the transverse cervicaltransverse cervical vessels, lymph nodes,vessels, lymph nodes, brachial plexusbrachial plexus
    30. 30. Supraclavicular TriangleSupraclavicular Triangle Boundaries:Boundaries: Above,Above, by the inferiorby the inferior belly of the Omohyoid;belly of the Omohyoid; Below,Below, by the clavicle;by the clavicle; BaseBase is formed by theis formed by the posterior border of theposterior border of the Sternocleidomastoid.Sternocleidomastoid. floorfloor is formed by theis formed by the first rib with the firstfirst rib with the first digitation of the Serratusdigitation of the Serratus anterior.anterior.
    31. 31.  Contents:Contents:  third portion of thethird portion of the subclavian artery,subclavian artery,  subclavian vein,subclavian vein,  cervical artery,cervical artery,  external jugular veinexternal jugular vein  lymph nodes.lymph nodes.